![[BACK]](/cvsweb/icons/back.gif){kind=icon}
Return to esis.4 CVS log ![[TXT]](/cvsweb/icons/text.gif){kind=icon}
![[DIR]](/cvsweb/icons/dir.gif){kind=icon}
Up to [CSRG BSD Unix] / 43BSDReno / share / man / man4|
Return to esis.4 CVS log | Up to [CSRG BSD Unix] / 43BSDReno / share / man / man4 |
1.1 root 1: .\" Copyright (c) 1990 The Regents of the University of California.
2: .\" All rights reserved.
3: .\"
4: .\" Redistribution and use in source and binary forms are permitted provided
5: .\" that: (1) source distributions retain this entire copyright notice and
6: .\" comment, and (2) distributions including binaries display the following
7: .\" acknowledgement: ``This product includes software developed by the
8: .\" University of California, Berkeley and its contributors'' in the
9: .\" documentation or other materials provided with the distribution and in
10: .\" all advertising materials mentioning features or use of this software.
11: .\" Neither the name of the University nor the names of its contributors may
12: .\" be used to endorse or promote products derived from this software without
13: .\" specific prior written permission.
14: .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
15: .\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
16: .\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
17: .\"
18: .\" @(#)esis.4 6.1 (Berkeley) 7/25/90
19: .\"
20: .TH TP 4 "July 25, 1990"
21: .UC 5
22: .SH NAME
23: es-is \- End System to Intermediate System Routing Protocol
24: .SH SYNOPSIS
25: .B "pseudo-device ether"
26: .SH DESCRIPTION
27: The ES-IS routing protocol is used to dynamically map between ISO NSAP
28: addresses and ISO SNPA addresses; to permit End and Intermediate Systems
29: to learn of each other's existence; and to allow Intermediate Systems
30: to inform End Systems of (potentially) better routes to use when
31: forwarding NPDUs to a particular destination.
32: .PP
33: The mapping between NSAP addresses and SNPA addresses is accomplished by
34: transmitting hello PDUs between the cooperating Systems. These PDUs
35: are transmitted whenever the \fIconfiguration\fR timer expires.
36: When a hello PDU is received, the SNPA
37: address that it conveys is stored in the routing table for as long as the
38: \fIholding time\fR in the PDU suggests. The default \fIholding time\fR
39: (120 seconds) placed in the hello PDU, the configuration timer value,
40: and the system type (End System or Intermediate System) may be changed by
41: issuing an SIOCSSTYPE ioctl(), which is defined in /sys/netiso/iso_snpac.h.
42: .PP
43: The protocol behaves differently depending on whether the System is
44: configured as an End System or an Intermediate System.
45: .SH "END SYSTEM OPERATION"
46: When an interface requests a mapping for an address not in the cache,
47: the SNPA of any known Intermediate System is returned. If an Intermediate
48: System is not known, then the \fIall end systems\fR multicast address
49: is returned. It is assumed that the intended recipient of the NPDU will
50: immediately transmit a hello PDU back to the originator of the NPDU.
51: .PP
52: If an NPDU is forwarded by the End System, a redirect PDU will not be
53: generated.
54: However, redirect PDUs received will be processed. This processing
55: consists of adding an entry in the routing table. If the
56: redirect is towards an Intermediate System, then an entry is made in the
57: routing table as well.
58: The entry in the routing table will may mark the
59: NSAP address contained in the redirect PDU as the gateway for the destination
60: system (if an NET is supplied), or will create a route with
61: the NSAP address as the
62: destination and the SNPA address (embodied as a link-level sockaddr) as the
63: gateway.
64: .PP
65: If the System is configured as an End System, it will report all the
66: NSAPs that have been configured using the ifconfig command, and no others.
67: It is possible to have more than one NSAP assigned to a given interface,
68: and it is also possible to have the same NSAP assigned to multiple
69: interfaces.
70: However, any NSAP containing an NSEL that is consistent with the
71: nsellength option (default one) of any interface will be accepted as
72: an NSAP for this System.
73: .SH "INTERMEDIATE SYSTEM OPERATION"
74: When an interface requests a mapping for an address not in the routing table,
75: an error is returned.
76: .PP
77: When an NPDU is forwarded out on the same interface that the NPDU arrived upon,
78: a redirect PDU is generated.
79: .SH "MANUAL ROUTING TABLE MODIFICATION"
80: .PP
81: To facilitate communications with systems which do not use ES-IS,
82: one may add a route whose destination is a sockaddr_iso containing
83: the NSAP in question, and the gateway being a link-level sockaddr,
84: either by writing a special purpose program, or using the
85: .IR route (8)
86: command e.g.:
87: .nf
88:
89: route add -iface -osi 49.0.4.8.0.2b.b.83.bf -link qe0:8.0.2b.b.83.bf
90: .fi
91: .PP
92: If the
93: System is configured as an End System and has a single network interface
94: which does not support multicast reception,
95: it is necessary to manually configure the location of an IS,
96: using the route command in a similar way.
97: There, the destination address should be ``default'' (spelled
98: out literally as 7 ascii characters), and the gateway should be
99: once again be a link-level sockaddr specifying the SNPA of the IS.
100: .SH SEE ALSO
101: un(4), iso(4F), route(8), ifconfig(8C)
102: .br
103: ``End system to Intermediate system routing exchange protocol
104: for use in conjunction with the Protocol for providing the
105: connectionless-mode network service'' (ISO 9542).
106: .SH BUGS
107: Redirect PDUs do not contain options from the forwarded NPDU which generated
108: the redirect. The multicast address used on the 802.3 network is taken from
109: the NBS December 1987 agreements. This multicast address is not compatible
110: with the 802.5 (Token Ring) multicast addresses format. Therefore, broadcast
111: addresses are used on the 802.5 subnetwork.
112: Researchers at the University of Wisconsin are constructing an implementation
113: of the IS-IS routing protocol.
This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.