RFC Errata
RFC 6822, "IS-IS Multi-Instance", December 2012
Note: This RFC has been obsoleted by RFC 8202
Source of RFC: isis (rtg)See Also: RFC 6822 w/ inline errata
Errata ID: 4520
Status: Verified
Type: Technical
Publication Format(s) : TEXT
Reported By: Alexander Okonnikov
Date Reported: 2015-11-02
Verifier Name: Alia Atlas
Date Verified: 2015-11-11
Section 2.6.1 says:
An MI-RTR will use the AllL1IS or AllL2IS ISIS MAC-layer address (as defined in [ISO10589]) as the destination address when sending an IS-IS PDU for the standard instance. An MI-RTR will use one of two new dedicated layer 2 multicast addresses (AllL1MI-ISs or AllL2MI- ISs) as the destination address when sending an IS-IS PDU for any non-zero IID. These addresses are specified in Section 6. If operating in point-to-point mode on a broadcast circuit [RFC5309], an MI-RTR MUST use one of the two new multicast addresses as the destination address when sending point-to-point IIHs associated with a non-zero instance. (Either address will do.) MI-RTRs MUST discard IS-IS PDUs received if either of the following is true: o The destination multicast address is AllL1IS or AllL2IS and the PDU contains an IID-TLV. o The destination multicast address is one of the two new addresses, and the PDU contains an IID-TLV with a zero value for the IID or has no IID-TLV. NOTE: If the multicast addresses AllL1IS and/or AllL2IS are improperly used to send IS-IS PDUs for non-zero IIDs, legacy systems will interpret these PDUs as being associated with IID #0. This will cause inconsistencies in the LSDB in those routers, may incorrectly maintain adjacencies, and may lead to inconsistent DIS election.
It should say:
An MI-RTR will use the AllL1ISs or AllL2ISs ISIS MAC-layer address (as defined in [ISO10589]) as the destination address when sending an IS-IS PDU for the standard instance. An MI-RTR will use one of two new dedicated layer 2 multicast addresses (AllL1MI-ISs or AllL2MI-ISs) as the destination address when sending an IS-IS PDU for any non-zero IID. These addresses are specified in Section 6. If operating in point-to-point mode on a broadcast circuit [RFC5309], an MI-RTR will use the AllL1ISs, AllL2ISs or AllISs MAC-layer address (as defined in [ISO10589]) as the destination address when sending an IS-IS PDU for the standard instance, and will use one of two new multicast addresses (AllL1MI-ISs or AllL2MI-ISs; either address will do) as the destination address when sending an IS-IS PDU for any non-zero IID. MI-RTRs MUST discard IS-IS PDUs received if either of the following is true: o The destination multicast address is AllL1ISs, AllL2ISs or AllISs and the PDU contains an IID-TLV. o The destination multicast address is one of the two new addresses and the PDU contains an IID-TLV with a zero value for the IID or has no IID-TLV. NOTE: If the multicast addresses AllL1ISs and/or AllL2ISs and/or AllISs are improperly used to send IS-IS PDUs for non-zero IIDs, legacy systems will interpret these PDUs as being associated with IID #0. This will cause inconsistencies in the LSDB in those routers, may incorrectly maintain adjacencies, and may lead to inconsistent DIS election.
Notes:
1. While operating in point-to-point mode over broadcast circuit, MI-RTR can use any of three multicast addresses for PDUs in standard instance - AllL1ISs, AllL2ISs or AllISs.
2. New multicast addresses must be used for all kinds of IS-IS PDUs, not only for IIHs
3. AllL1IS and AllL2IS are replaced by AllL1ISs and AllL2ISs, respectively (according to ISO 10589:2002).