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RPF check with equal IGP cost links, how is RPFcalculated?

Question is: how is rpf calculated?

Got 2 routers with 2 serials links with same bandwich

Routing is due to 2 static routers to the Loopback addresses and BGP is running between the loopback addresses.

Pim spare-mode is every ware enabled.

According to the book Developing IP Multicast Networks volume 1 page 134

The rpf should point to the highest next hop ip address.

But in real live my rpf is pointed to the lowers address, of miss I something?

Ip number 138.55.130.250 is loopback of router2

Router1>sh ip rou 138.55.130.250

Routing entry for 138.55.130.250/32

Known via "static", distance 1, metric 0 (connected)

Routing Descriptor Blocks:

directly connected, via Serial0/1.801

Route metric is 0, traffic share count is 1

* directly connected, via Serial0/0.701

Route metric is 0, traffic share count is 1

SGSGPUE2MP999>sh ip rpf 138.55.130.250

RPF information for router2 (138.55.130.250)

RPF interface: Serial0/1.801

RPF neighbor: router2 (138.55.132.13)

RPF route/mask: 138.55.130.250/32

RPF type: unicast (static)

RPF recursion count: 0

Doing distance-preferred lookups across tables

Router1>sh ip int brief

Serial0/0.701 138.55.132.66 --> highest ip address!

Serial0/1.801 138.55.132.14

Loopback0 161.126.91.62

2 REPLIES
Bronze

Re: RPF check with equal IGP cost links, how is RPFcalculated?

The following link provides information on RPF troubleshooting

Multiple Equal Cost Paths Result in Unwanted Return Path Forwarding Behavior

http://www.cisco.com/warp/public/105/mcastguide4.html

IP Multicast Troubleshooting Guide

http://www.cisco.com/en/US/tech/tk648/tk363/technologies_tech_note09186a0080094b55.shtml

New Member

Re: RPF check with equal IGP cost links, how is RPFcalculated?

Both links explain that the RPF pointed to the highest next hop ip address.

in my example it's the Lowers IP address....

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