Glossary
G
31 terms.
- Galois Counter Mode
A way of using a block cipher such as AES that encrypts data and also produces an authentication tag, so one operation gives both secrecy and tamper detection.
Like I'm five A lock that also adds a tamper seal while it locks.
- Galois Field
A finite field, a set with a fixed number of elements where addition and multiplication are defined. GF(2^8) has 256 elements, each represented as a byte.
Like I'm five A small number system where the answers always stay inside the same little set of numbers.
- Gateway
The older name, used in RFC 791 and RFC 792, for a device that forwards datagrams between networks. Today it is called a router.
Like I'm five A door between two neighborhoods that passes packages along.
Used in RFC 675 RFC 777 RFC 781 RFC 791 RFC 792 RFC 810 RFC 811 RFC 814 RFC 816 RFC 823 RFC 824 RFC 827 RFC 828 RFC 831 RFC 840 RFC 872 RFC 875 RFC 879 RFC 888 RFC 891 RFC 896 RFC 898 RFC 904 RFC 911 and 200 more
- Generalized TTL Security Mechanism
A defense that sends packets with the maximum TTL or Hop Limit (255) and drops those that arrive with a lower value, so only directly connected senders are accepted.
Like I'm five A check that a message really came from next door and not from far away.
- Generic Associated Channel
A control channel carried in-band alongside an LSP, pseudowire or section, used for OAM and similar adjunct traffic. It is signaled by an Associated Channel Header and a G-ACh Label.
Like I'm five A side lane on the same road that carries inspector messages instead of cargo.
- Generic Routing Encapsulation (GRE)
A tunnelling method that wraps packets of an arbitrary protocol inside IP so they can cross a network that does not understand them.
Like I'm five Putting one kind of letter inside another kind of envelope so it can travel on a different mail route.
- Geneve
Generic Network Virtualization Encapsulation, a flexible and extensible overlay protocol that encapsulates network packets for transport across underlying physical networks.
Like I'm five A wrapper that lets one network ride inside another.
- Geolocation
Determining the geographic location of a device, usually expressed as latitude and longitude with associated uncertainty.
Like I'm five Figuring out where something is on Earth.
- Glare
A clash that happens when both sides try to send a new offer at the same time. The higher layer protocol has to resolve it.
Like I'm five Two people both start talking at once, so someone has to decide who goes first.
- Glue record
An IP address published in a parent zone for a name server whose name lies inside the zone it serves, so that resolvers can find the server at all.
Like I'm five A phone number written next to a name so you can actually call it.
Used in RFC 1912 RFC 3375 RFC 3732 RFC 4697 RFC 4932 RFC 5732 RFC 5936 RFC 7477 RFC 9471 RFC 9499 RFC 10001
- Glyph
The visual shape of a single character or symbol in a font. A font file contains glyphs for many characters.
Like I'm five The picture of a letter or symbol that a font displays.
- GMAC
The message authentication mode of Galois/Counter Mode. It authenticates data without encrypting anything and produces an authentication tag.
Like I'm five A tamper-proof seal that proves a message was not changed.
- GMPLS
Generalized Multi-Protocol Label Switching extends the MPLS control plane beyond packets to time-division, wavelength and fiber switching.
Like I'm five A way of booking routes through light and glass, using the same ideas that MPLS uses for packets.
Used in RFC 3473 RFC 4204 RFC 4783 RFC 4847 RFC 5146 RFC 5150 RFC 5307 RFC 5818 RFC 6001 RFC 6004 RFC 6005 RFC 6060 RFC 6163 RFC 6344 RFC 6387 RFC 6457 RFC 6689 RFC 6827 RFC 7025 RFC 7096 RFC 7139 RFC 7167 RFC 7579 RFC 7580 and 4 more
- Go Ahead (GA)
The Telnet command (249) a process sends when it has finished sending output and has nothing queued from the keyboard, so a half-duplex terminal knows to pass control back to the user.
Like I'm five Saying "over" on a walkie-talkie so the other person knows it is their turn.
Used in RFC 560 RFC 596 RFC 726 RFC 764 RFC 854 RFC 857 RFC 858 RFC 1043
- GOAWAY
An HTTP/3 control stream frame (type 0x07) that tells the peer to stop starting new requests so the connection can shut down gracefully, while requests already in flight can finish.
Like I'm five Saying "we're closing, finish what you started."
Used in RFC 9114
- Goodput
The application-layer throughput delivered to the destination, excluding retransmitted or lost bits.
Like I'm five The actual useful data that gets through, not counting lost or resent packets.
- Gopher
An early Internet protocol for browsing menus of documents and directories and for searching them. It was widely implemented in the early 1990s.
Like I'm five An old way of clicking through menus of files on the internet before the web took over.
- Grace period
A window after a registry action during which the client can delete the object and receive a credit for what that action cost. EPP defines several, such as the add and renew periods.
Like I'm five A short time after you buy something when you can return it and get your money back.
- Graceful restart
A way for a router to restart its control plane while its neighbors and its own forwarding keep working, so traffic is not disrupted.
Like I'm five Rebooting the brain without stopping the hands.
Used in RFC 3478 RFC 3612 RFC 3623 RFC 4167 RFC 5063 RFC 5187 RFC 5495 RFC 5882 RFC 8538 RFC 8706 RFC 9494
- Grandmaster clock
A master clock that gets its time from a locally attached clock device, not through the network, and then distributes that time to other clocks.
Like I'm five The main clock that every other clock copies.
- Grant type
In OAuth, a method a client uses to obtain an access token. RFC 6749 defines authorization code, implicit, resource owner password credentials and client credentials.
Like I'm five One of several different ways of getting a pass.
- Granule position
An increasing position number stored in an Ogg page header, whose meaning depends on the codec of that logical bitstream.
Like I'm five A page number on a bookmark that only the book's own reader knows how to read.
- Gratuitous ARP
An ARP packet a host sends about its own address without anyone asking, used to refresh other hosts' tables or to notice that another host already uses the same address. Common practice; RFC 826 does not use this name.
Like I'm five Standing up and announcing 'I am sitting here!' before anybody asks.
Used in RFC 826 RFC 2002 RFC 2006 RFC 2281 RFC 2338 RFC 3344 RFC 3927 RFC 5227 RFC 5798 RFC 5944 RFC 6820 RFC 7342 RFC 8302 RFC 8388 RFC 9047 RFC 9135 RFC 9161 RFC 9568
- GRE
Generic Routing Encapsulation, a protocol for wrapping an arbitrary protocol inside another arbitrary network-layer protocol so it can cross a network as a tunnel.
Like I'm five A way to put one kind of mail inside an envelope of another kind so it can travel through a pipe.
- GREASE
"Generate Random Extensions And Sustain Extensibility", the practice of sending reserved or random values so that implementations keep handling unknown ones correctly (RFC 8701). ECH clients send a GREASE ECH extension when they have no real configuration.
Like I'm five Wiggling a stuck door every so often so it never gets rusty and stops opening.
- Group Controller and Key Server (GCKS)
The entity that authenticates and authorizes members of a secure group, creates the group's keys, and distributes them in registration and rekey messages.
Like I'm five The club leader who checks who may enter and hands out the secret password.
- Group Security Association (GSA)
The set of security associations for a secure group, made up of a Registration SA, an optional Rekey SA and a Data SA.
Like I'm five The whole bundle of agreements that lets a group talk secretly.
- GRTT
The group round-trip time, a conservative estimate by the sender of the worst-case round trip from the sender to any receiver in the group. NACK timers are scaled from it.
Like I'm five How long it takes a shout to reach the farthest kid and an answer to come back.
- GRUU
A Globally Routable User Agent URI is an address that identifies one specific SIP user agent instance and can be reached from anywhere. It is defined in RFC 5627.
Like I'm five A direct address that always reaches one particular person, not just their household.
Used in RFC 5359 RFC 5627 RFC 5628 RFC 5767 RFC 6665 RFC 7247 RFC 7572 RFC 7647 RFC 7904
- GSS-API
Generic Security Service Application Program Interface, a standard API that lets applications use different security mechanisms underneath, such as Kerberos or NTLM.
Like I'm five A standard way for programs to ask for security without needing to know which security method is available.
Used in RFC 1961 RFC 1964 RFC 2025 RFC 2078 RFC 2203 RFC 2478 RFC 2743 RFC 2744 RFC 2847 RFC 3645 RFC 4121 RFC 4178 RFC 4401 RFC 4462 RFC 5056 RFC 5178 RFC 5403 RFC 5587 RFC 5801 RFC 6339 RFC 6649 RFC 6680 RFC 7055 RFC 7802 and 3 more