[20484] in North American Network Operators' Group
Re: IGPs in use
daemon@ATHENA.MIT.EDU (Tony Li)
Wed Oct 14 16:49:34 1998
To: xxvaf@WR.BBNPLANET.COM (Vince Fuller)
cc: nanog@merit.edu
From: Tony Li <tli@juniper.net>
Date: 14 Oct 1998 13:32:00 -0700
In-Reply-To: xxvaf@WR.BBNPLANET.COM's message of 14 Oct 98 19:57:01 GMT
xxvaf@WR.BBNPLANET.COM (Vince Fuller) writes:
> There are some drawbacks to IS-IS: ...
>
> IS-IS uses an underlying traffic exchange which is based on OSI/CLNS. This
> introduces requirements for OSI addressing and CLNS implementation which are
> otherwise useless in an IP-centric network. IMHO, this represents a
> substantial bit of operational complexity (obtaining CLNS addresses, teaching
> operations/engineering staff how to use them and interpret them while
> debugging, etc., etc...)
While it does require OSI addressing, it does not require CLNP forwarding.
As to the engineering and operations aspects, the additional complexity
can, with a reasonable implementation, be almost completely hidden. For
example:
> show isis adjacency
IS-IS adjacency database:
Interface System L State Hold (secs) SNPA
fxp0.0 lab5 2 Up 16 0:0:c0:cc:a0:bf
fxp0.0 lab2 2 Up 25 0:0:c0:e8:69:db
fxp0.0 lab10 1 Up 22 0:a0:c9:36:b3:a6
> On a pragmatic note, though, the relative successes of IS-IS and OSPF in the
> large provider marketplace probably has more to do with the relative competence
> of the cisco's original OSPF and IS-IS implementors than anything else
> (only someone else who suffered through OSPF's growing pains way back in
> the 9.0-9.1 days can really appreciate this comment...)
Very true, tho those of us who had ringside seats do sympathize. ;-)
Tony
