MOSPF can't determine the receiving interface exactly - In John Moy's book OSPF Anatomy of a Routing Protocol
Ian Potts <ijpotts_lists@YAHOO.CO.UK> Thu, 05 June 2003 12:51 UTC
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From: Ian Potts <ijpotts_lists@YAHOO.CO.UK>
Subject: MOSPF can't determine the receiving interface exactly - In John Moy's book OSPF Anatomy of a Routing Protocol
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Hello, In John Moy's excellent book, Anatomy of an Internet Routing Protocol, on page 195 (section 10.3.1 The Multicast Forwarding Cache), it states that a router does the RPF check in MOSPF on the router's ID, and not on the incoming interface, since MOSPF can't determine the receiving interface exactly, since there is insufficient information in the OSPF lsdb to match the sending and receiving halves. Can someone please explain this to me since I am confused. Looking at the router LSAs given below, can't the router first work out the router-id, then consult the routing table to find the interface? Many Thanks Ian Router 1 Link connected to: another Router (point-to-point) (Link ID) Neighboring Router ID: 144.141.252.254 (Link Data) Router Interface address: 144.128.254.138 Number of TOS metrics: 0 TOS 0 Metrics: 1000 Link connected to: a Stub Network (Link ID) Network/subnet number: 144.128.254.136 (Link Data) Network Mask: 255.255.255.248 Number of TOS metrics: 0 TOS 0 Metrics: 1000 Router 2 Link connected to: another Router (point-to-point) (Link ID) Neighboring Router ID: 144.141.89.2 (Link Data) Router Interface address: 144.128.254.137 Number of TOS metrics: 0 TOS 0 Metrics: 1000 Link connected to: a Stub Network (Link ID) Network/subnet number: 144.128.254.136 (Link Data) Network Mask: 255.255.255.248 Number of TOS metrics: 0 TOS 0 Metrics: 1000 __________________________________________________ Yahoo! Plus - For a better Internet experience http://uk.promotions.yahoo.com/yplus/yoffer.html
- MOSPF can't determine the receiving interface exa… Ian Potts
- Re: MOSPF can't determine the receiving interface… Yasuhiro Ohara