Ethan Banks On productivity. CCIE-LAB List – Best of 1/4/2008 – Prefix-list Tutorial + Sink RP + IOS Privileges + Where To Enable Bidir PIM


Here’s what most interested me as I read through GroupStudy CCIE-LAB list posts today.

  • A tutorial on prefix lists. If you are having a hard time with what the “le” and “ge” will actually match at the end of a prefix list entry, this is a good read.
  • Cisco recommends the configuration of a “sink RP” when running sparse-dense mode. The sink RP is effectively a blackhole that will prevent multicast groups that have not been assigned to an RP from falling back to dense-mode flooding. Click here, then scroll down to the section Sparse-Dense Mode For Auto-RP for more information on the “sink RP” concept.
  • If you see a frame-relay task instructing you to “not send any redundant broadcast traffic from the spokes to the hub”, you need to think about where you’re using the “broadcast” keyword on your frame-relay map ip statements.
  • Link to a nice article about IOS privilege levels, explaining why a non-level 15 user might only see parts of a config when doing a “show run”.
  • In bidir-PIM, do all the routers need to have bidir-PIM enabled, or just the RP? The answer is all interfaces that are to participate in bidir-PIM need to have it enabled. Just the RP is not enough. This makes perfect sense when you read through all of what goes on regarding election of a designated forwarder for a multicast group, plus just understanding what’s going on with bidir-PIM – it wouldn’t work right unless all the routers potentially involved were playing by the same set of forwarding rules.
By Ethan Banks
Ethan Banks On productivity.

You probably know Ethan Banks because he writes & podcasts about IT. For example, he co-authored "Computer Networks Problems & Solutions" with Russ White.

This site is Ethan on productivity--not tech so much.

Find out more on his about page.