RFC 6984 INFORMATIONAL FORCES · INTEROPERABILITY · ROUTING
ForCES Interop: Interoperability Report for Forwarding and Control Element Separation (ForCES)
Three independent ForCES implementations swap roles in a February 2011 test and report what worked, what failed and what they learned.
RFC EDITOR
Wang, W., Ogawa, K., Haleplidis, E., Gao, M., and J. Hadi Salim, "Interoperability Report for Forwarding and Control Element Separation (ForCES)", RFC 6984, DOI 10.17487/RFC6984, August 2013, <https://www.rfc-editor.org/info/rfc6984>.
BIBTEX
@misc{rfc6984,
series = {Request for Comments},
number = 6984,
howpublished = {RFC 6984},
publisher = {RFC Editor},
doi = {10.17487/RFC6984},
url = {https://www.rfc-editor.org/info/rfc6984},
author = {W. Wang and K. Ogawa and E. Haleplidis and M. Gao and J. Hadi Salim},
title = {{Interoperability Report for Forwarding and Control Element Separation (ForCES)}},
pagetotal = 29,
year = 2013,
month = aug,
} LINEAGE · FROM THE RFC INDEXOpen full graph →
RFC text
Contents
Internet Engineering Task Force (IETF) W. Wang
Request for Comments: 6984 Zhejiang Gongshang University
Updates: 6053 K. Ogawa
Category: Informational NTT Corporation
ISSN: 2070-1721 E. Haleplidis
University of Patras
M. Gao
Hangzhou BAUD Networks
J. Hadi Salim
Mojatatu Networks
August 2013
Interoperability Report
for Forwarding and Control Element Separation (ForCES)
Abstract
This document captures the results of the second Forwarding and
Control Element Separation (ForCES) interoperability test that took
place on February 24-25, 2011, in the Internet Technology Lab (ITL)
at Zhejiang Gongshang University, China. The results of the first
ForCES interoperability test were reported in RFC 6053, and this
document updates RFC 6053 by providing further interoperability
results.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6984.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. ForCES Protocol . . . . . . . . . . . . . . . . . . . . . 3
1.2. ForCES FE Model . . . . . . . . . . . . . . . . . . . . . 4
1.3. Transport Mapping Layer . . . . . . . . . . . . . . . . . 4
1.4. Definitions . . . . . . . . . . . . . . . . . . . . . . . 4
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Date, Location, and Participants . . . . . . . . . . . . . 4
2.2. Testbed Configuration . . . . . . . . . . . . . . . . . . 5
2.2.1. Participants' Access . . . . . . . . . . . . . . . . . 5
2.2.2. Testbed Configuration . . . . . . . . . . . . . . . . 6
3. Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1. Scenario 1 - LFB Operation . . . . . . . . . . . . . . . . 7
3.2. Scenario 2 - TML with IPsec . . . . . . . . . . . . . . . 8
3.3. Scenario 3 - CE High Availability . . . . . . . . . . . . 9
3.4. Scenario 4 - Packet Forwarding . . . . . . . . . . . . . . 11
4. Test Results . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.1. Test of LFB Operation . . . . . . . . . . . . . . . . . . 14
4.2. Test of TML with IPsec . . . . . . . . . . . . . . . . . . 20
4.3. Test of CE High Availability . . . . . . . . . . . . . . . 20
4.4. Test of Packet Forwarding . . . . . . . . . . . . . . . . 21
5. Discussions . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.1. On Data Encapsulation Format . . . . . . . . . . . . . . . 23
6. Security Considerations . . . . . . . . . . . . . . . . . . . 26
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7.1. Normative References . . . . . . . . . . . . . . . . . . . 26
7.2. Informative References . . . . . . . . . . . . . . . . . . 26
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 28
Appendix B. Contributors . . . . . . . . . . . . . . . . . . . . 28
1. Introduction
This document captures the results of the second interoperability
test of the Forwarding and Control Element Separation (ForCES) that
took place on February 24-25, 2011, in the Internet Technology Lab
(ITL) at Zhejiang Gongshang University, China. The test involved
protocol elements described in several documents, namely:
- ForCES Protocol [RFC5810]
- ForCES Forwarding Element (FE) Model [RFC5812]
- ForCES Transport Mapping Layer (TML) [RFC5811]
The test also involved protocol elements described in the then-
current versions of two Internet-Drafts. Although these documents
have subsequently been revised and advanced, it is important to
understand which versions of the work were used during this test.
The then-current Internet-Drafts are:
- "ForCES Logical Function Block (LFB) Library" (December 2010)
[LFB-LIB]
- "ForCES Intra-NE High Availability" (October 2010) [CEHA]
Note: The ForCES Logical Function Block (LFB) Library document was
published as [RFC6956].
Three independent ForCES implementations participated in the test.
Scenarios of ForCES LFB Operation, TML with IPsec, Control Element
High Availability (CEHA), and Packet Forwarding were constructed.
Series of testing items for every scenario were carried out and
interoperability results were achieved. The popular packet analyzers
Ethereal/Wireshark [Ethereal] and Tcpdump [Tcpdump] were used to
verify the wire results.
This document is an update to [RFC6053], which captured the results
of the first ForCES interoperability test. The first test on ForCES
was held in July 2008 at the University of Patras, Greece. That test
focused on validating the basic semantics of the ForCES protocol and
ForCES Forwarding Element (FE) model.
1.1. ForCES Protocol
The ForCES protocol works in a master-slave mode in which FEs are
slaves and Control Elements (CEs) are masters. The protocol includes
commands for transport of Logical Function Block (LFB) configuration
information, association setup, status, event notifications, etc.
The reader is encouraged to read the ForCES protocol specification
[RFC5810] for further information.
1.2. ForCES FE Model
The ForCES FE model [RFC5812] presents a formal way to define FE LFBs
using XML. LFB configuration components, capabilities, and
associated events are defined when the LFB is formally created. The
LFBs within the FE are accordingly controlled in a standardized way
by the ForCES protocol.
1.3. Transport Mapping Layer
The ForCES Transport Mapping Layer (TML) transports the ForCES
protocol layer messages. The TML is where the issues of how to
achieve transport-level reliability, congestion control, multicast,
ordering, etc., are handled. It is expected that more than one TML
will be standardized. RFC 5811 specifies a TML that is based on the
Stream Control Transmission Protocol (SCTP) and is a mandated TML for
ForCES. See RFC 5811 for more details.
1.4. Definitions
This document follows the terminology defined by ForCES-related
documents, including [RFC3654], [RFC3746], [RFC5810], [RFC5811],
[RFC5812], [RFC5813], etc.
2. Overview
2.1. Date, Location, and Participants
The second ForCES interoperability test meeting was held by the IETF
ForCES Working Group on February 24-25, 2011, and was chaired by
Jamal Hadi Salim. Three independent ForCES implementations
participated in the test:
o Zhejiang Gongshang University/Hangzhou BAUD Corporation of
Information and Networks Technology (Hangzhou BAUD Networks),
China. This implementation is referred to as "ZJSU" or "Z" in
this document for the sake of brevity.
o NTT Corporation, Japan. This implementation is referred to as
"NTT" or "N" in this document for the sake of brevity.
o The University of Patras, Greece. This implementation is referred
to as "UoP" or "P" in this document for the sake of brevity.
Two other organizations, Mojatatu Networks and Hangzhou BAUD Networks
Corporation, which independently extended two different well-known
public domain protocol analyzers, Ethereal/Wireshark [Ethereal] and
Tcpdump [Tcpdump], also participated in the interoperability test.
During the test, the two protocol analyzers were used to verify the
validity (and in some cases, the semantics) of ForCES protocol
messages.
Some issues related to interoperability among implementations were
discovered. Most of the issues were solved on site during the test.
The most contentious issue found was on the format of encapsulation
for the protocol TLVs (refer to Section 5.1).
Some errata related to the ForCES document were found by the
interoperability test. The errata found in related RFCs have also
been reported.
At times, interoperability testing was exercised between two instead
of all three representative implementations because the third one
lacked a specific feature; however, in ensuing discussions, all
implementers mentioned they would be implementing any missing
features in the future.
2.2. Testbed Configuration
2.2.1. Participants' Access
NTT and ZJSU were physically present for the testing at the Internet
Technology Lab (ITL) at Zhejiang Gongshang University in China. The
implementation team from the University of Patras joined remotely
from Greece. The chair, Jamal Hadi Salim, joined remotely from
Canada by using TeamViewer as the monitoring tool [TeamViewer]. The
approach was as shown in Figure 1. In the figure, FE/CE refers to
the FE or CE that the implementer may act as alternatively.
+---------+ +----+ +------------+
| FE/CE | | | +---| Monitoring |
| ZJSU |-----| | /\/\/\/\/\ | |(TeamViewer)|
+---------+ | | \Internet/ | | Mojatatu |
|LAN |----/ \--| +------------+
+---------+ | | \/\/\/\/\/ | +------------+
| FE/CE |-----| | | | FE/CE |
| NTT | | | +---| UoP |
+---------+ +----+ +------------+
Figure 1: Access for Participants
As specified in [RFC5811], all CEs and FEs implemented IPsec in the
TML.
On the Internet boundary, gateways used must allow for IPsec, the
SCTP protocol, and SCTP ports as defined in the ForCES SCTP-based TML
document [RFC5811].
2.2.2. Testbed Configuration
The CEs and FEs from ZJSU's and NTT's implementations were physically
located within the ITL Lab at Zhejiang Gongshang University and
connected together using Ethernet switches. The configuration can be
seen in Figure 2. In the figure, SmartBits [SmartBits] is a third-
party routing protocol testing machine that acts as a router running
Open Shortest Path First (OSPF) and RIP, and exchanges routing
protocol messages with ForCES routers in the network. Connection to
the Internet was via an Asymmetric Digital Subscriber Line (ADSL)
channel.
/\/\/\/\/\
\Internet/
/ \
\/\/\/\/\/
|
|(ADSL)
|
+-------------------------------------------------------------------+
| LAN (10.20.0.0/24) |
+-------------------------------------------------------------------+
| | | | | |
| | | | | |
|.222 |.230 |.221 |.179 |.231 |.220
+-----+ +-----+ +-----+ +-----+ +-----+ +---------+
| CE | | CE | | | | | | | | Protocol|
|ZJSU | | NTT | | FE1 |.1 .2| FE |.1 .2| FE2 | | Analyzer|
+-----+ +-----+ |ZJSU |---------| NTT |---------|ZJSU | +---------+
+---------| |192.169. | | 192.168.| |------+
| .2 +-----+ 20.0.24 +-----+ 30.0/24+-----+ .2 |
| .12| |.12 |
| | | |
192.168.50.0/24 | |192.168.60.0/24
| 192.168.10.0/24 192.168.40.0/24 |
.1 | |.11 |.11 |.1
+--------+ +--------------------------------------+ +--------+
|Terminal| | SmartBits | |Terminal|
+--------+ +--------------------------------------+ +--------+
Figure 2: Testbed Configuration Located in the ITL Lab, China
The CE and FE from the UoP implementation were located within the
University of Patras, Greece, and were connected together using LAN,
as shown in Figure 3. Connection to the Internet was via a VPN
channel.
/\/\/\/\/\
\Internet/
/ \
\/\/\/\/\/
|
|(VPN)
|
+------------------------------------+
| LAN |
+------------------------------------+
| | |
| | |
+------+ +--------+ +------+
| FE | |Protocol| | CE |
| UoP | |Analyzer| | UoP |
+------+ +--------+ +------+
Figure 3: Testbed Configuration
Located in the University of Patras, Greece
The testbeds above were then able to satisfy the requirements of all
interoperability test scenarios in this document.
3. Scenarios
3.1. Scenario 1 - LFB Operation
This scenario was designed to test the interoperability of LFB
operations among the participants. The connection diagram for the
participants is shown in Figure 4.
+------+ +------+ +------+ +------+ +------+ +------+
| CE | | CE | | CE | | CE | | CE | | CE |
| ZJSU | | NTT | | ZJSU | | UoP | | NTT | | UoP |
+------+ +------+ +------+ +------+ +------+ +------+
| | | | | |
| | | | | |
+------+ +------+ +------+ +------+ +------+ +------+
| FE | | FE | | FE | | FE | | FE | | FE |
| NTT | | ZJSU | | UoP | | ZJSU | | UoP | | NTT |
+------+ +------+ +------+ +------+ +------+ +------+
Figure 4: Scenario for LFB Operation
In order to make interoperability more credible, the three
implementers were required to carry out the test acting as a CE or FE
alternatively. As a result, every LFB operation was combined with
six scenarios, as shown by Figure 4.
The test scenario was designed with the following purposes.
Firstly, the scenario was designed to verify all kinds of protocol
messages with their complex data formats, which were defined in
[RFC5810]. Specifically, we tried to verify the data format of a
PATH-DATA-TLV with nested PATH-DATA-TLVs, and the operation (SET,
GET, and DEL) of an array or an array with a nested array.
Secondly, the scenario was designed to verify the definition of
ForCES LFB Library [LFB-LIB], which defined a base set of ForCES LFB
classes for typical router functions. Successful tests under this
scenario would help the validity of the LFB definitions.
3.2. Scenario 2 - TML with IPsec
This scenario was designed to implement a TML with IPsec, which was
the requirement defined by RFC 5811. TML with IPsec was not
implemented and tested in the first ForCES interoperability test, as
reported in RFC 6053. For this reason, in this interoperability
test, we specifically designed the test scenario to verify the TML
over IPsec channel.
In this scenario, tests on LFB operations for Scenario 1 were
repeated with the difference that TML was secured via IPsec. This
setup scenario allowed us to verify whether all interactions between
the CE and FE could be made correctly under an IPsec TML environment.
The connection diagram for this scenario is shown in Figure 5.
Because an unfortunate problem with the test system in the UoP
prevented the deployment of IPsec over TML, this test only took place
between the test systems in ZJSU and NTT.
+------+ +------+
| CE | | CE |
| ZJSU | | NTT |
+------+ +------+
| |
|TML over IPsec |TML over IPsec
+------+ +------+
| FE | | FE |
| NTT | | ZJSU |
+------+ +------+
Figure 5: Scenario for LFB Operation with TML over IPsec
In this scenario, ForCES TML was run over the IPsec channel.
Implementers joined in this interoperability test using the same
third-party software 'Racoon' [Racoon] to establish the IPsec
channel.
The Racoon in NetBSD is an Internet Key Exchange (IKE) daemon that
performs the key exchange with the peers. Both IKEv1 and IKEv2 are
supported by Racoon in Linux 2.6, and IKEv2 was adopted in the
interop test. The Security Association Database (SAD) and Security
Policy Database (SPD) were necessary for the test, setups of which
were in the Racoon configuration file. The Encapsulating Security
Payload (ESP) was specified in the SAD and SPD in the Racoon
configuration file.
ZJSU and NTT conducted a successful test with the scenario, and the
IPsec requirement items in [RFC5812] were realized.
3.3. Scenario 3 - CE High Availability
CE High Availability (CEHA) was tested based on the ForCES CEHA
document [CEHA].
The design of the setup and the scenario for the CEHA were simplified
so as to focus mostly on the mechanics of the CEHA, which were:
o Associating with more than one CE.
o Switching to a backup CE on a master CE failure.
The connection diagram for the scenario is shown in Figure 6.
master standby master standby
+------+ +------+ +------+ +------+
| CE | | CE | | CE | | CE |
| ZJSU | | UoP | | NTT | | UoP |
+------+ +------+ +------+ +------+
| | | |
+----------+ +-----------+
| |
+------+ +------+
| FE | | FE |
| UoP | | UoP |
+------+ +------+
(a) (b)
Figure 6: Scenario for CE High Availability
In this scenario, one FE was connected and associated to a master CE
and a backup CE. In the pre-association phase, the FE would be
configured to have ZJSU's or NTT's CE as the master CE and the UoP's
CE as the standby CE. The CEFailoverPolicy component of the FE
Protocol Object LFB that specified whether the FE was in High
Availability mode (value 2 or 3) would be set either in the pre-
association phase by the FE interface or in the post-association
phase by the master CE.
If the CEFailoverPolicy value was set to 2 or 3, the FE (in the post-
association phase) would attempt to connect and associate with the
standby CE.
When the master CE was deemed disconnected, either by a TearDown,
Loss of Heartbeats, or physically disconnected, the FE would assume
that the standby CE was now the master CE. The FE would then send an
Event Notification, Primary CE Down, to all associated CEs (only the
standby CE in this case) with the value of the new master Control
Element ID (CEID). The standby CE would then respond by sending a
configuration message to the CEID component of the FE Protocol Object
with its own ID to confirm that the CE considered itself the master
as well.
The steps of the CEHA test scenario were as follows:
1. In the pre-association phase, the FE is set up with the master CE
and the backup CE.
2. The FE connects and associates with the master CE.
3. When CEFailoverPolicy is set to 2 or 3, the FE connects and
associates with the backup CE.
4. Once the master CE is considered disconnected, then the FE
chooses the first associated backup CE.
5. It sends an Event Notification that specifies the master CE is
down and identifies the new master CE.
6. The new master CE sends a SET Configuration message to the FE;
the FE then sets the CEID value to the new master CE completing
the switch.
3.4. Scenario 4 - Packet Forwarding
This test scenario was conducted to verify LFBs like RedirectIn,
RedirectOut, IPv4NextHop, and IPv4UcastLPM, which were defined by the
ForCES LFB library document [LFB-LIB], and more importantly, to
verify the combination of the LFBs to implement IP packet forwarding.
The connection diagram for this scenario is shown in Figure 7.
+------+
| CE |
| NTT |
+------+
| ^
| | OSPF
| +------->
+------+ +------+
+--------+ | FE | | OSPF | +--------+
|Terminal|------| ZJSU |-------|Router|------|Terminal|
+--------+ +------+ +------+ +--------+
<-------------------------------------------->
Packet Forwarding
(a)
+------+
| CE |
| ZJSU |
+------+
^ | ^
OSPF | | | OSPF
<-----+ | +----->
+-------+ +------+ +------+
+--------+ | OSPF | | FE | | OSPF | +--------+
|Terminal|----|Router |----| NTT |-----|Router|--|Terminal|
+--------+ +-------+ +------+ +------+ +--------+
<-------------------------------------------->
Packet Forwarding
(b)
+------+ +------+
| CE | | CE |
| NTT | | ZJSU |
+------+ +------+
| ^ ^ |
| | OSPF | |
| +----------+ |
+------+ +------+
+--------+ | FE | | FE | +--------+
|Terminal|------| ZJSU |-------| NTT |------|Terminal|
+--------+ +------+ +------+ +--------+
<-------------------------------------------->
Packet Forwarding
(c)
Figure 7: Scenario for IP Packet Forwarding
In case (a), NTT's CE was connected to ZJSU's FE to form a ForCES
router. A SmartBits [SmartBits] test machine equipped with routing
protocol software was used to simulate an OSPF router and was
connected with the ForCES router to try to exchange OSPF Hello
packets and Link State Advertisement (LSA) packets among them.
Terminals were simulated by SmartBits to send and receive packets.
As a result, the CE in the ForCES router needed to be configured to
run and support the OSPF routing protocol.
In case (b), ZJSU'S CE was connected to NTT'S FE to form a ForCES
router. Two routers running OSPF were simulated and connected to the
ForCES router to test if the ForCES router could support the OSPF
protocol and support packet forwarding.
In case (c), two ForCES routers were constructed; one was with NTT's
CE and ZJSU's FE, and the other was with NTT's FE and ZJSU's CE.
OSPF and packet forwarding were tested in the environment.
The testing process for this scenario is shown below:
1. Boot terminals and routers, and set the IP addresses of their
interfaces.
2. Boot the CE and FE.
3. Establish an association between the CE and FE, and set the IP
addresses of the FE interfaces.
4. Start OSPF among the CE and routers, and set the Forwarding
Information Base (FIB) on the FE.
5. Send packets between terminals.
4. Test Results
4.1. Test of LFB Operation
The test results are reported in Figure 8. As mentioned earlier, for
convenience, the following abbreviations are used in the table: "Z"
for the implementation from ZJSU, "N" for the implementation from
NTT, and "P" for the implementation from the UoP.
+-----+----+-----+-----+--------------+-------------------+---------+
|Test#| CE |FE(s)|Oper | LFB | Component | Result |
| | | | | | /Capability | |
+-----+----+-----+-----+--------------+-------------------+---------+
| 1 | Z | N | GET | FEObject | LFBTopology | Success |
| | N | Z | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 2 | Z | N | GET | FEObject | LFBSelector | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 3 | Z | N | GET | EtherPHYCop | PHYPortID | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 4 | Z | N | GET | EtherPHYCop | AdminStatus | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 5 | Z | N | GET | EtherPHYCop | OperStatus | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 6 | Z | N | GET | EtherPHYCop | AdminLinkSpeed | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 7 | Z | N | GET | EtherPHYCop | OperLinkSpeed | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 8 | Z | N | GET | EtherPHYCop | AdminDuplexSpeed | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 9 | Z | N | GET | EtherPHYCop | OperDuplexSpeed | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 10 | Z | N | GET | EtherPHYCop | CarrierStatus | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 11 | Z | N | GET | EtherMACIn | AdminStatus | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 12 | Z | N | GET | EtherMACIn | LocalMacAddresses | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 13 | Z | N | GET | EtherMACIn | L2Bridging | Success |
| | N | Z | | | PathEnable | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 14 | Z | N | GET | EtherMACIn | PromiscuousMode | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 15 | Z | N | GET | EtherMACIn | TxFlowControl | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 16 | Z | N | GET | EtherMACIn | RxFlowControl | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 17 | Z | N | GET | EtherMACIn | MACInStats | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 18 | Z | N | GET | EtherMACOut | AdminStatus | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 19 | Z | N | GET | EtherMACOut | MTU | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 20 | Z | N | GET | EtherMACOut | TxFlowControl | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 21 | Z | N | GET | EtherMACOut | TxFlowControl | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 22 | Z | N | GET | EtherMACOut | MACOutStats | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 23 | Z | N | GET | ARP |PortV4AddrInfoTable| Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 24 | Z | N | SET | ARP |PortV4AddrInfoTable| Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 25 | Z | N | DEL | ARP |PortV4AddrInfoTable| Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 26 | Z | N | SET | EtherMACIn | LocalMACAddresses | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 27 | Z | N | SET | EtherMACIn | MTU | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 28 | Z | N | SET | IPv4NextHop | IPv4NextHopTable | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 29 | Z | N | SET | IPv4UcastLPM | IPv4PrefixTable | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 30 | Z | N | DEL | IPv4NextHop | IPv4NextHopTable | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 31 | Z | N | DEL | IPv4UcastLPM | IPv4PrefixTable | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 32 | Z | N | SET | EtherPHYCop | AdminStatus | Success |
| | N | Z | | | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 33 | Z | N | SET | Ether | VlanInputTable | Success |
| | N | Z | | Classifier | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 34 | Z | N | DEL | Ether | VlanInputTable | Success |
| | N | Z | | Classifier | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 35 | Z | N | SET | Ether | VlanOutputTable | Success |
| | N | Z | | Encapsulator | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
| | | | | | | |
| 36 | Z | N | DEL | Ether | VlanOutputTable | Success |
| | N | Z | | Encapsulator | | Success |
| | Z | P | | | | Success |
| | P | Z | | | | Success |
| | N | P | | | | Success |
| | P | N | | | | Success |
+-----+----+-----+-----+--------------+-------------------+---------+
Figure 8: Test Results for LFB Operation
Note on tests #1 and #2:
On the wire format of encapsulation on array, only the case of
FULLDATA-TLV vs. SPARSEDATA-TLV was tested.
When we use the ForCES protocol, it is very common for the CE to use
the FEobject LFB to get information on LFBs and their topology in the
FE. Hence, the two tests were specifically made.
4.2. Test of TML with IPsec
In this scenario, the ForCES TML was run over IPsec. Implementers
joined this interoperability test and used the same third-party tool
software 'Racoon' [Racoon] to establish the IPsec channel. Typical
LFB operation tests as in Scenario 1 were repeated with the
IPsec-enabled TML.
As mentioned, this scenario only took place between implementers from
ZJSU and NTT.
The TML with IPsec test results are reported in Figure 9.
+-----+----+-----+-----+--------------+-------------------+---------+
|Test#| CE |FE(s)|Oper | LFB | Component/ | Result |
| | | | | | Capability | |
+-----+----+-----+-----+--------------+-------------------+---------+
| 1 | Z | N | GET | FEObject | LFBTopology | Success |
| | N | Z | | | | Success |
| | | | | | | |
| 2 | Z | N | GET | FEObject | LFBSelectors | Success |
| | N | Z | | | | Success |
| | | | | | | |
| 3 | Z | N | SET | Ether | VlanInputTable | Success |
| | N | Z | | Classifier | | Success |
| | | | | | | |
| 4 | Z | N | DEL | Ether | VlanInputTable | Success |
| | N | Z | | Classifier | | Success |
+-----+----+-----+-----+--------------+-------------------+---------+
Figure 9: Test Results for TML with IPsec
4.3. Test of CE High Availability
In this scenario, one FE connected and associated with a master CE
and a backup CE. When the master CE was deemed disconnected, the FE
attempted to find another associated CE to become the master CE.
The CEHA scenario, as described in Scenario 3, was completed
successfully for both setups.
Due to a bug in one of the FEs, an interesting issue was caught: it
was observed that the buggy FE took up to a second to failover. It
was eventually found that the issue was due to the FE's
prioritization of the different CEs. All messages from the backup CE
were being ignored unless the master CE was disconnected.
While the bug was fixed and the CEHA scenario was completed
successfully, the authors felt it was important to capture the
implementation issue in this document. The recommended approach is
the following:
o The FE should receive and handle messages first from the master CE
on all priority channels to maintain proper functionality and then
receive and handle messages from the backup CEs.
o Only when the FE is attempting to associate with the backup CEs
should the FE receive and handle messages per priority channel
from all CEs. When all backup CEs are associated with or deemed
unreachable, then the FE should return to receiving and handling
messages first from the master CE.
4.4. Test of Packet Forwarding
As described in the ForCES LFB library [LFB-LIB], packet forwarding
is implemented by a set of LFB classes that compose a processing path
for packets. In this test scenario, as shown in Figure 7, a ForCES
router running the OSPF protocol was constructed. In addition, a set
of LFBs including RedirectIn, RedirectOut, IPv4UcastLPM, and
IPv4NextHop were used. RedirectIn and RedirectOut LFBs redirected
OSPF Hello and LSA packets from and to the CE. A SmartBits
[SmartBits] test machine was used to simulate an OSPF router and
exchange the OSPF Hello and LSA packets with the CE in the ForCES
router.
In Figure 7, cases (a) and (b) both need a RedirectIn LFB to send
OSPF packets generated by the CE to the FE by use of ForCES packet
redirect messages. The OSPF packets were further sent to an outside
OSPF router by the FE via forwarding LFBs, including IPv4NextHop and
IPv4UcastLPM. A RedirectOut LFB in the FE was used to send OSPF
packets received from outside the OSPF router to the CE by ForCES
packet redirect messages.
By running OSPF, the CE in the ForCES router could generate new
routes and load them to the routing table in the FE. The FE was then
able to forward packets according to the routing table.
The test results are shown in Figure 10.
+-----+----+-----+-------------------------+--------------+---------+
|Test#| CE |FE(s)| Item | LFBs Related | Result |
+-----+----+-----+-------------------------+--------------+---------+
| 1 | N | Z | IPv4NextHopTable SET | IPv4NextHop | Success |
| | | | | | |
| 2 | N | Z | IPv4PrefixTable SET | IPv4UcastLPM | Success |
| | | | | | |
| 3 | N | Z |Redirect OSPF packet from| RedirectIn | Success |
| | | | CE to SmartBits | | |
| | | | | | |
| 4 | N | Z |Redirect OSPF packet from| RedirectOut | Success |
| | | | SmartBits to CE | | |
| | | | | | |
| 5 | N | Z | Metadata in | RedirectOut | Success |
| | | | redirect message | RedirectIn | |
| | | | | | |
| 6 | N | Z | OSPF neighbor discovery | RedirectOut | Success |
| | | | | RedirectIn | |
| | | | | | |
| 7 | N | Z | OSPF DD exchange | RedirectOut | Success |
| | | | | RedirectIn | |
| | | | | IPv4NextHop | |
| | | | | | |
| 8 | N | Z | OSPF LSA exchange | RedirectOut | Success |
| | | | | RedirectIn | |
| | | | | IPv4NextHop | |
| | | | | IPv4UcastLPM| |
| | | | | | |
| 9 | N | Z | Data Forwarding | RedirectOut | Success |
| | | | | RedirectIn | |
| | | | | IPv4NextHop | |
| | | | | IPv4UcastLPM| |
| | | | | | |
| 10 | Z | N | IPv4NextHopTable SET | IPv4NextHop | Success |
| | | | | | |
| 11 | Z | N | IPv4PrefixTable SET | IPv4UcastLPM| Success |
| | | | | | |
| 12 | Z | N |Redirect OSPF packet from| RedirectIn | Success |
| | | | CE to other OSPF router | | |
| | | | | | |
| 13 | Z | N |Redirect OSPF packet from| RedirectOut | Success |
| | | |other OSPF router to CE | | |
| | | | | | |
| 14 | Z | N | Metadata in | RedirectOut | Success |
| | | | redirect message | RedirectIn | |
| | | | | | |
| 15 | Z | N |OSPF neighbor discovery | RedirectOut | Success |
| | | | | RedirectIn | |
| | | | | | |
| 16 | Z | N | OSPF DD exchange | RedirectOut | Failure |
| | | | | RedirectIn | |
| | | | | IPv4NextHop | |
| | | | | | |
| 17 | Z | N | OSPF LSA exchange | RedirectOut | Failure |
| | | | | RedirectIn | |
| | | | | IPv4NextHop | |
| | | | | IPv4UcastLPM| |
+-----+----+-----+-------------------------+--------------+---------+
Figure 10: Test Results for Packet Forwarding
Note on tests #3 to #9:
During the test, OSPF packets received from the CE were found by
Ethereal/Wireshark to have checksum errors in the FE. Because the
test time was quite limited, the implementer of the CE did not make
an effort to find and solve the checksum error; instead, the FE had
tried to correct the checksum in order to not let the SmartBits drop
the packets. Note that such a solution does not affect the test
results.
Comment on tests #16 and #17:
The two test items failed. Note that tests #7 and #8 were identical
to tests #16 and #17, only with CE and FE implementers being
exchanged. Moreover, tests #12 and #13 showed that the redirect
channel worked well. Therefore, it can be reasonably inferred that
the problem caused by the failure was from the implementations,
rather than from the ForCES protocol itself or the misunderstanding
of implementations on the protocol specification. Although the
failure made the OSPF interoperability test incomplete, it did not
show an interoperability problem. More test work is needed to verify
the OSPF interoperability.
5. Discussions
5.1. On Data Encapsulation Format
On the first day of the test, it was found that the LFB
interoperations pertaining to tables all failed. It was eventually
found that the failure occurred because different data encapsulation
methods for ForCES protocol messages were used by different
implementations. The issue is described in detail below.
Assuming that an LFB has two components, one is a struct with ID=1
and the other is an array with ID=2; in addition, both have two
components of u32 inside, as shown below:
struct1: type struct, ID=1
components are:
a, type u32, ID=1
b, type u32, ID=2
table1: type array, ID=2
components for each row are (a struct of):
x, type u32, ID=1
y, type u32, ID=2
1. On Response of PATH-DATA-TLV Format
When a CE sends a config/query ForCES protocol message to an FE from
a different implementer, the CE probably receives a response from the
FE with a different PATH-DATA-TLV encapsulation format. For example,
if a CE sends a query message with a path of 1 to a third-party FE to
manipulate struct1 as defined above, it is probable that the FE will
generate a response with two different PATH-DATA-TLV encapsulation
formats: one is the value with FULLDATA-TLV/SPARSEDATA-TLV and the
other is the value with many parallel PATH-DATA-TLVs and nested
PATH-DATA-TLVs, as shown below:
format 1:
OPER = GET-RESPONSE-TLV
PATH-DATA-TLV:
IDs=1
FULLDATA-TLV containing valueof(a),valueof(b)
format 2:
OPER = GET-RESPONSE-TLV
PATH-DATA-TLV:
IDs=1
PATH-DATA-TLV:
IDs=1
FULLDATA-TLV containing valueof(a)
PATH-DATA-TLV:
IDs=2
FULLDATA-TLV containing valueof(b)
The interoperability testers witnessed that a ForCES element (CE or
FE) sender is free to choose whatever data structure that IETF ForCES
documents define and best suits the element, while a ForCES element
(CE or FE) should be able to accept and process information (requests
and responses) that use any legitimate structure defined by IETF
ForCES documents. While in the case where a ForCES element is free
to choose any legitimate data structure as a response, it is
preferred that the ForCES element responds in the same format that
the request was made, as it is most likely the data structure that
the request sender looks to receive.
2. On Operation to Array
An array operation may also have several different data encapsulation
formats. For instance, if a CE sends a config message to table1 with
a path of (2.1), which refers to the component with ID=2 (an array),
and the second ID is the row, then row 1 may be encapsulated with
three formats as shown below:
format 1:
OPER = SET-TLV
PATH-DATA-TLV:
IDs=2.1
FULLDATA-TLV containing valueof(x),valueof(y)
format 2:
OPER = SET-TLV
PATH-DATA-TLV:
IDs=2.1
PATH-DATA-TLV:
IDs=1
FULLDATA-TLV containing valueof(x)
PATH-DATA-TLV
IDs=2
FULLDATA-TLV containing valueof(y)
Moreover, if the CE is targeting the whole array, for example, if the
array is empty and the CE wants to add the first row to the table, it
could also adopt another format:
format 3:
OPER = SET-TLV
PATH-DATA-TLV:
IDs=2
FULLDATA-TLV containing rowindex=1,valueof(x),valueof(y)
The interoperability test experience has shown that formats 1 and 3,
which take full advantage of the multiple data elements description
in one TLV of FULLDATA-TLV, are more efficient, although format 2 can
also achieve the same operating goal.
6. Security Considerations
Developers of ForCES FEs and CEs must take the security
considerations of the ForCES Framework [RFC3746] and ForCES Protocol
Specification [RFC5810] into account. Also, as specified in the
security considerations of SCTP-Based TML for the ForCES Protocol
[RFC5811], the transport-level security has to be ensured by IPsec.
Test results of TML with IPsec supported have been shown in
Section 4.2 in this document.
The tests described in this document used only simple password
security mode. Testing using more sophisticated security is for
future study.
Further testing using key agility is encouraged. The tests reported
here used SCTP TML running over an IPsec tunnel, which was
established by Racoon. Key negotiation formed part of this process,
but we believe that the SCTP TML used does not include key agility or
renegotiation.
7. References
7.1. Normative References
[RFC5810] Doria, A., Hadi Salim, J., Haas, R., Khosravi, H.,
Wang, W., Dong, L., Gopal, R., and J. Halpern,
"Forwarding and Control Element Separation (ForCES)
Protocol Specification", RFC 5810, March 2010.
[RFC5811] Hadi Salim, J. and K. Ogawa, "SCTP-Based Transport
Mapping Layer (TML) for the Forwarding and Control
Element Separation (ForCES) Protocol", RFC 5811,
March 2010.
[RFC5812] Halpern, J. and J. Hadi Salim, "Forwarding and Control
Element Separation (ForCES) Forwarding Element Model",
RFC 5812, March 2010.
[RFC5813] Haas, R., "Forwarding and Control Element Separation
(ForCES) MIB", RFC 5813, March 2010.
7.2. Informative References
[CEHA] Ogawa, K., Wang, W., Haleplidis, E., and J. Salim,
"ForCES Intra-NE High Availability", Work in Progress,
October 2010.
[Ethereal] Fenggen, J., "Subject: Release of a test version of
ForCES dissector based on Ethereal 0.99.0", message to
the IETF forces mailing list, 11 June 2009,
<http://www.ietf.org/mail-archive/web/forces/current/
msg03687.html>.
[LFB-LIB] Wang, W., Haleplidis, E., Ogawa, K., Li, C., and J.
Halpern, "ForCES Logical Function Block (LFB) Library",
Work in Progress, December 2010.
[RFC3654] Khosravi, H. and T. Anderson, "Requirements for
Separation of IP Control and Forwarding", RFC 3654,
November 2003.
[RFC3746] Yang, L., Dantu, R., Anderson, T., and R. Gopal,
"Forwarding and Control Element Separation (ForCES)
Framework", RFC 3746, April 2004.
[RFC6053] Haleplidis, E., Ogawa, K., Wang, W., and J. Hadi Salim,
"Implementation Report for Forwarding and Control
Element Separation (ForCES)", RFC 6053, November 2010.
[RFC6956] Wang, W., Haleplidis, E., Ogawa, K., Li, C., and J.
Halpern, "Forwarding and Control Element Separation
(ForCES) Logical Function Block (LFB) Library",
RFC 6956, June 2013.
[Racoon] The NetBSD Foundation, "How to build a remote user
access VPN with Racoon",
<http://www.netbsd.org/docs/network/ipsec/rasvpn.html>.
[SmartBits] Spirent Inc., "The Highly-Scalable Router Performance
Tester: TeraRouting Tester", 2005,
<http://www.spirent.com/~/media/Datasheets/Broadband/
Obsolete_SMB-TM/TeraRouting%20Tester.pdf>.
[Tcpdump] Hadi Salim, J., "Subject: tcpdump 4.1.1", message to
the IETF forces mailing list, 20 May 2010,
<http://www.ietf.org/mail-archive/web/forces/current/
msg03811.html>.
[TeamViewer] TeamViewer Inc., "TeamViewer - the All-In-One Software
for Remote Support and Online Meetings",
<http://www.teamviewer.com/>.
Appendix A. Acknowledgements
The authors thank the following test participants:
Chuanhuang Li, Hangzhou BAUD Networks
Ligang Dong, Zhejiang Gongshang University
Bin Zhuge, Zhejiang Gongshang University
Jingjing Zhou, Zhejiang Gongshang University
Liaoyuan Ke, Hangzhou BAUD Networks
Kelei Jin, Hangzhou BAUD Networks
The authors also thank very much Adrian Farrel, Joel Halpern, Ben
Campbell, Nevil Brownlee, and Sean Turner for their important help in
the document publication process.
Appendix B. Contributors
Contributors who have made major contributions to the
interoperability test are listed below.
Hirofumi Yamazaki
NTT Corporation
Tokyo
Japan
EMail: yamazaki.horofumi@lab.ntt.co.jp
Rong Jin
Zhejiang Gongshang University
Hangzhou
P.R. China
EMail: jinrong@zjsu.edu.cn
Yuta Watanabe
NTT Corporation
Tokyo
Japan
EMail: yuta.watanabe@ntt-at.co.jp
Xiaochun Wu
Zhejiang Gongshang University
Hangzhou
P.R. China
EMail: spring-403@zjsu.edu.cn
Authors' Addresses
Weiming Wang
Zhejiang Gongshang University
18 Xuezheng Str., Xiasha University Town
Hangzhou 310018
P.R. China
Phone: +86-571-28877721
EMail: wmwang@zjsu.edu.cn
Kentaro Ogawa
NTT Corporation
Tokyo
Japan
EMail: ogawa.kentaro@lab.ntt.co.jp
Evangelos Haleplidis
University of Patras
Department of Electrical & Computer Engineering
Patras 26500
Greece
EMail: ehalep@ece.upatras.gr
Ming Gao
Hangzhou BAUD Networks
408 Wen-San Road
Hangzhou 310012
P.R. China
EMail: gaoming@mail.zjgsu.edu.cn
Jamal Hadi Salim
Mojatatu Networks
Ottawa
Canada
EMail: hadi@mojatatu.com
AI ELI5
On this page
PROBLEMForCES separates the control part of a router from its forwarding part, and independent implementations needed to show that they really work together.
MECHANISMThree implementations from China, Japan and Greece were tested on February 24-25, 2011, across four scenarios: LFB operations, TML over IPsec, control element high availability and packet forwarding with OSPF.
WHAT CAME OUT OF ITNearly all tests succeeded. Two OSPF exchange tests between one pairing failed, which the authors attribute to implementations rather than the protocol. A disagreement on TLV encapsulation was the most contentious issue.
§1What the Test Covered
RFC 6984 reports the second interoperability test of Forwarding and Control Element Separation (ForCES), held on February 24-25, 2011 at the Internet Technology Lab at Zhejiang Gongshang University in China. It updates RFC 6053, which reported the first test (July 2008, University of Patras, Greece) and focused on the basic semantics of the protocol and forwarding element model.
In ForCES, Control Elements (CEs) are masters and Forwarding Elements (FEs) are slaves. The test used the protocol (RFC 5810), the FE model (RFC 5812) and the SCTP-based Transport Mapping Layer (RFC 5811), plus then-current drafts of the Logical Function Block (LFB) library and CE high availability, with the LFB library later published as RFC 6956. Three independent implementations took part, and Wireshark and Tcpdump extensions were used to verify what was on the wire.
Grown-ups who build network gear met to check that their separately made parts really fit together, and wrote a report.
§2Participants and Testbed
The participants were Zhejiang Gongshang University with Hangzhou BAUD Networks (ZJSU), NTT Corporation (NTT) and the University of Patras (UoP). ZJSU and NTT were on site in China. The UoP team joined remotely from Greece, and the working group chair monitored remotely from Canada using TeamViewer.
The ZJSU and NTT elements were connected by Ethernet switches, with a SmartBits test machine acting as a router running OSPF and RIP and an ADSL link to the Internet. The UoP elements sat on a LAN in Greece connected over a VPN. Gateways had to allow IPsec, SCTP and the SCTP ports defined in RFC 5811. Sometimes only two of the three implementations could be tested because the third lacked a feature.
Two teams sat in the same room and one joined by video call from another country. They plugged their machines together and used a special tester that pretended to be other routers.
§3The Four Test Scenarios
Scenario 1, LFB operation. Each implementer acted as both CE and FE, giving six pairings, to verify the protocol's complex data formats such as nested PATH-DATA-TLVs and operations (SET, GET and DEL) on arrays and nested arrays. All 36 listed tests succeeded in every pairing.
Scenario 2, TML with IPsec. The LFB tests were repeated with the TML secured by IPsec, using the Racoon IKE daemon with IKEv2 and ESP. A problem with the UoP system meant only ZJSU and NTT took part, and the four tests succeeded.
Scenario 3, CE high availability. One FE associated with a master CE and a backup CE. When the master was deemed disconnected, the FE promoted the backup, sent a Primary CE Down event and the new master confirmed itself with a SET. This passed. A bug in one FE caused failover to take up to a second because it ignored backup CE messages until the master was gone, so the RFC recommends handling master CE messages first while still receiving backup CE messages when associating.
Scenario 4, packet forwarding. Routers built from one party's CE and another's FE ran OSPF and forwarded packets through the RedirectIn, RedirectOut, IPv4UcastLPM and IPv4NextHop LFBs. Tests 16 and 17, the OSPF database description and LSA exchanges for one pairing, failed. The authors infer an implementation problem, not a protocol problem, and say more OSPF testing is needed.
They tried four games: asking and changing settings, doing it with a secret tunnel, switching to a spare boss when the first one drops out, and passing real traffic. Almost every game worked, and a couple of bits in the last one did not.
Master CEFEBackup CE
- Connect and associateSet up in the pre-association phase.
- Connect and associateWhen CEFailoverPolicy is 2 or 3.
- Event: Primary CE DownSent after the master is deemed disconnected; carries the new master CEID.
- SET Configuration (its own CEID)Completes the switch to the new master.
§5The Encapsulation Format Issue
On the first day, every LFB operation involving tables failed. The cause was that implementations used different but legitimate ways of encapsulating data in ForCES messages. For example, a response about a struct can be one FULLDATA-TLV holding all component values, or many parallel and nested PATH-DATA-TLVs, one per component. An array row can likewise be written in several forms.
The testers concluded that a sender is free to choose any structure the IETF ForCES documents define, but a receiver should accept and process any legitimate structure. When free to choose, it is preferred to answer in the same format as the request. For arrays, the formats that put several values in one FULLDATA-TLV proved more efficient, though the nested form also works.
Two people wrote the same address in two different but allowed ways, and each could not read the other's. The fix is simple: write it however you like, but be able to read every allowed way.
§6Security Notes
Developers must take into account the security considerations of the ForCES framework (RFC 3746) and protocol specification (RFC 5810). Because RFC 5811 requires transport-level security by IPsec, the TML with IPsec results in Section 4.2 are the security-relevant part of the tests.
The tests used only simple password security mode, and testing more sophisticated security is left for future study. Further testing with key agility is encouraged: the SCTP TML over an IPsec tunnel established by Racoon included key negotiation, but the authors believe the SCTP TML itself does not include key agility or renegotiation.
They only tried the basic lock, not the fancier ones, so they suggest trying those next time.
§6References
[RFC6053]RFC 6053Haleplidis, E., Ogawa, K., Wang, W., and J. Hadi Salim, "Implementation Report for Forwarding and Control Element Separation (ForCES)", RFC 6053, November 2010.November 2010[RFC5810]RFC 5810Doria, A., Hadi Salim, J., Haas, R., Khosravi, H., Wang, W., Dong, L., Gopal, R., and J. Halpern, "Forwarding and Control Element Separation (ForCES) Protocol Specification", RFC 5810, March 2010.March 2010[RFC5811]RFC 5811Hadi Salim, J. and K. Ogawa, "SCTP-Based Transport Mapping Layer (TML) for the Forwarding and Control Element Separation (ForCES) Protocol", RFC 5811, March 2010.March 2010[RFC5812]RFC 5812Halpern, J. and J. Hadi Salim, "Forwarding and Control Element Separation (ForCES) Forwarding Element Model", RFC 5812, March 2010.March 2010[RFC6956]RFC 6956Wang, W., Haleplidis, E., Ogawa, K., Li, C., and J. Halpern, "Forwarding and Control Element Separation (ForCES) Logical Function Block (LFB) Library", RFC 6956, June 2013.June 2013