IL (network protocol)

{{Short description|A transport-layer protocol designed at Bell Labs for the Plan 9 operating system}}

{{Infobox networking protocol

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| abbreviation = IL

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| osilayer = Transport layer (4)

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The Internet Link protocol or IL is a connection-based transport-layer protocol designed at Bell Labs originally as part of the Plan 9 operating system and is used to carry 9P. It is assigned the Internet Protocol number of 40. It is similar to TCP but much simpler.

Its main features are:

Reliable datagram service
In-sequence delivery
Internetworking using IP
Low complexity, high performance
Adaptive timeouts

As of the Fourth Edition of Plan 9, 2003, IL is deprecated in favor of TCP/IP because it doesn't handle long-distance connections well.{{cite web |url=https://9p.io/sys/doc/release4.html |title=Plan 9 — Fourth Edition Release Notes |publisher=Lucent Technologies |date=June 2003 |access-date=August 3, 2018 |quote=We are phasing out the IL protocol since it doesn’t handle long-distance connections well (and long-distance networks don't handle it well, either). IL is still used by fs(4) but TCP has become the standard protocol for all other services. }}

Header

{{APHD|0|bits1=8|bits2=8|bits3=16|field1=Version and header length|field2=Type of service|field3=Packet length}}

{{APHD|4|bits1=16|bits2=16|field1=Identification|field2=Fragment information}}

{{APHD|8|bits1=8|bits2=8|bits3=16|field1=Time to live|field2=Protocol|field3=Header checksum}}

{{APHD|20|bits1=16|bits2=16|field1=Checksum including header|field2=Packet length}}

{{APHD|24|bits1=8|bits2=8|bits3=16|field1=Packet type|field2=Special|field3=Src port}}

{{APHD|28|bits1=16|bits2=32|field1=Dst port|field2=Sequence id|border2=right}}

struct IPIL

{

byte vihl; /* Version and header length */

byte tos; /* Type of service */

byte length[2]; /* packet length */

byte id[2]; /* Identification */

byte frag[2]; /* Fragment information */

byte ttl; /* Time to live */

byte proto; /* Protocol */

byte cksum[2]; /* Header checksum */

byte src[4]; /* Ip source */

byte dst[4]; /* Ip destination */

byte ilsum[2]; /* Checksum including header */

byte illen[2]; /* Packet length */

byte iltype; /* Packet type */

byte ilspec; /* Special */

byte ilsrc[2]; /* Src port */

byte ildst[2]; /* Dst port */

byte ilid[4]; /* Sequence id */

byte ilack[4]; /* Acked sequence */

};

IL (network protocol)

Header

See also

References

Further reading