Re: bgp dmzlink-bw verification

From: Tim Chan (timanji@yahoo.com)
Date: Thu Oct 19 2006 - 00:32:23 ART


No, I was not able to find out why this is happening.

----- Original
Message ----
From: Nick Griffin <nick.jon.griffin@gmail.com>
To: Tim Chan
<timanji@yahoo.com>
Cc: ccielab@groupstudy.com
Sent: Wednesday, October 18,
2006 8:29:29 PM
Subject: Re: bgp dmzlink-bw verification

Tim, were you ever
to make sense out of this? I just did a similar
scenario and notice the same
thing. Anyone have an thoughts/suggestions?

R5#sh ip bgp 100.100.100.0

BGP
routing table entry for 100.100.100.0/24, version 15

Paths: (2 available,
best #1, table Default-IP-Routing-Table)

Multipath: eBGP iBGP

  Not
advertised to any peer

  900

    192.168.75.7 from 192.168.75.7
(192.168.97.7)

      Origin IGP, metric 0, localpref 100, valid, internal,
multipath, best

      DMZ-Link Bw 12 kbytes

  900

    192.168.85.8 from
192.168.85.8 (192.168.98.8)

      Origin IGP, metric 0, localpref 100, valid,
internal, multipath

      DMZ-Link Bw 1 kbytes

R5#sh ip route
100.100.100.0

Routing entry for 100.100.100.0/24

  Known via "bgp 1000",
distance 200, metric 0

  Tag 900, type internal

  Last update from
192.168.85.8 00:06:08 ago

  Routing Descriptor Blocks:

    192.168.75.7,
from 192.168.75.7, 00:06:08 ago

      Route metric is 0, traffic share count
is 1

      AS Hops 1

  * 192.168.85.8, from 192.168.85.8, 00:06:08 ago
Route metric is 0, traffic share count is 12

      AS Hops 1

On 10/17/06,
Tim Chan <timanji@yahoo.com> wrote:
Hi all,

I'm trying to understand the
output I'm getting when I configure "bgp
dmzlink-bw".
After my configuration
is done, I get the following output:
R2#sho ip bgp 0.0.0.0

BGP routing table
entry for 0.0.0.0/0, version 32
Paths: (2 available, best #2, table
Default-IP-Routing-Table)
Multipath: iBGP
Flag: 0x800
  Advertised to non
peer-group peers:

  145.1.245.5
  100,
(Received from a RR-client)
145.1.245.5 from 145.1.245.5 (
150.1.5.5)
Origin IGP, metric 0, localpref 100,
valid, internal, multipath
      DMZ-Link
Bw 1 kbytes
  100, (Received from a
RR-client)
    145.1.245.4 from

145.1.245.4 (150.1.4.4)
      Origin IGP,
metric 0, localpref 100, valid,
internal, multipath, best
      DMZ-Link Bw
1250 kbytes

You can see that the
route to R5 is 1kbps and R4 is 1250kbps.
So when I do a "show ip route", I
get the following:
R2#sho ip route 0.0.0.0
Routing entry for 0.0.0.0/0,
supernet
  Known via "bgp 200", distance 200,
metric 0, candidate default path

Tag 100, type internal
  Last update from
145.1.245.4 00:00:28 ago
  Routing
Descriptor Blocks:
  * 145.1.245.5, from
145.1.245.5, 00:00:28 ago
      Route
metric is 0, traffic share count is 10
AS Hops 1
    145.1.245.4, from
145.1.245.4, 00:00:28 ago

      Route metric
is 0, traffic share count is 1
AS Hops 1

Note that I'm getting a traffic
share count of 10:1. Which looks
good, BUT, the 10 is
towards the slower
link, not the faster one. So normally

I would read this as, "For every
10
packets sent to R5, send 1 packet to R4."
But this makes no sense!

In looking
at the doccd, the output in the examples
follows what makes sense. The faster
links get the larger ratios.
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t
/122t2/ftbgplb.htm#wp1052316

This is from IE Vol2 Lab 6, task 4.9. And even
their verification output shows the same
10:1 favor over the slower link. Are
these outputs correct and I'm just reading it wrong?
(But then the doccd shows
otherwise)

Please advise...
-Tim



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