Kevin Dorrell, CCIE #20765

20 Apr 2008

NMC DOiT 16.5 EIGRP

Filed under: EIGRP, IP Routing Protocols — dorreke @ 09:10

I did have a momentary panic in the EIGRP section over “16.5.2 Send a summary for the entire Class B range from R2 to CAT2 only.”

For a start, I misinterpreted it as meaning 160.60.0.0/16, the major network of the pod.  So I did an ip summary-address eigrp 1 160.60.0.0 255.255.0.0 on R2-F0/0.  Of course, the summary turned up not only in CAT2, but in R1 and everywhere else as well.  I could have filtered it toward R1, but that seemed like too much work.  What I wanted to do was to get rid of the discard route on R2.  Could I remember how to do it?  No!  So it took some research to remind myself of ip summary-address eigrp 1 160.60.0.0 255.255.0.0 255.  Setting the AD to 255 stops the discard route getting into the routing table, and so stops it getting redistributed into OSPF.

All well.  But futile.  On reconsideration, what they wanted was a range that covered all the Class-B addresses.  In other words, ip summary-address eigrp 1 128.0.0.0 192.0.0.0 255.  Later, I checked it against the SHOWiT, and found they did not put in the AD=255.  So, doesn’t that make the /2 summary route turn up in R1?  Instead of putting AD=255, they take the precaution  of filtering it during the redistribution from EIGRP to OSPF.  The difference my AD=255 makes is whether the discard route gets installed in R2.

 

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1 Comment »

  1. […] 16.5 EIGRP […]

    Pingback by NMC DOiT Lab 16 « Kevin Dorrell’s CCIE Study Weblog — 20 Apr 2008 @ 13:41


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