IS-IS metric

gojericho0gojericho0 Member Posts: 1,059 ■■■□□□□□□□
in CCNP
I have never used this in a production network, but since the metric (10 by default) is the same on all routers this seems like nothing more than a hop count. Has anyone used this routing protocol before and do you change this default metric or leave it alone? From what I can tell it looks like it has to be the same on all routers and this could lead to bad routing decisions.
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  • networker050184networker050184 Mod Posts: 11,962 Mod
    When ever I have used OSPF or IS-IS I always set the cost manually. It adds for better control of routing and it was the way I was taught so I guess it kind of stuck.
    An expert is a man who has made all the mistakes which can be made.
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  • Paul BozPaul Boz Member Posts: 2,620 ■■■■■■■■□□
    The ISIS metric is left intentionally low to encourage admins to manually adjust to suit their networks. Also, the default seed-metric for ISIS when doing redistribution is zero, so if you don't specify a seed metric when redistributing into ISIS none of your external routes will show up. Some admins hate it and some love it. It forces you to get much more granular than a lot of people like to get. Read up on the timers also. ISIS is a fantastic protocol if you're a config nerd.
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