Re: Per-destination loadbalancing

From: Jesper Skriver (jesper@skriver.dk)
Date: Tue Jul 25 2000 - 11:05:57 EDT


On Tue, Jul 25, 2000 at 10:33:34AM -0400, De Troch, Bruno wrote:
> Does anyone knows how per-destination loadbalancing is done on 7513 with cef
> enabled?
> Suppose I have 2 static routes defined on 2 equal speed serial links. Is it
> possible to predict which link will be chosen if I know source and
> destination ip addresses/subnets?

No, it depends on the source/destination addressed hashed into some hash
buckets, as you can see below it depends on which hash bucket the source
address fall's into.

aegnxt1#sh ip cef 195.249.0.37 internal
195.249.0.37/32, version 79480, per-destination sharing
0 packets, 0 bytes
  tag information set, shared
    local tag: 71
  via 195.249.6.254, Serial1/7:1, 28 dependencies
    traffic share 1
    next hop 195.249.6.254, Serial1/7:1
    valid adjacency
    tag rewrite with Se1/7:1, point2point, tags imposed: {}
  via 195.249.6.250, Serial1/6:1, 27 dependencies
    traffic share 1
    next hop 195.249.6.250, Serial1/6:1
    valid adjacency
    tag rewrite with Se1/6:1, point2point, tags imposed: {}

  0 packets, 0 bytes switched through the prefix
  tmstats: external 0 packets, 0 bytes
           internal 0 packets, 0 bytes
  Load distribution: 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 (refcount 56)

  Hash OK Interface Address Packets Tags imposed
  1 Y Serial1/7:1 point2point 0 none
  2 Y Serial1/6:1 point2point 0 none
  3 Y Serial1/7:1 point2point 0 none
  4 Y Serial1/6:1 point2point 0 none
  5 Y Serial1/7:1 point2point 0 none
  6 Y Serial1/6:1 point2point 0 none
  7 Y Serial1/7:1 point2point 0 none
  8 Y Serial1/6:1 point2point 0 none
  9 Y Serial1/7:1 point2point 0 none
  10 Y Serial1/6:1 point2point 0 none
  11 Y Serial1/7:1 point2point 0 none
  12 Y Serial1/6:1 point2point 0 none
  13 Y Serial1/7:1 point2point 0 none
  14 Y Serial1/6:1 point2point 0 none
  15 Y Serial1/7:1 point2point 0 none
  16 Y Serial1/6:1 point2point 0 none

/Jesper

-- 
Jesper Skriver, jesper(at)skriver(dot)dk  -  CCIE #5456
Work:    Network manager @ AS3292 (Tele Danmark DataNetworks)
Private: Geek            @ AS2109 (A much smaller network ;-)

One Unix to rule them all, One Resolver to find them, One IP to bring them all and in the zone to bind them.



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