[24216] in North American Network Operators' Group
Re: OSPF multi-level hierarchy: Necessary at all?
daemon@ATHENA.MIT.EDU (Alex P. Rudnev)
Mon May 31 06:19:30 1999
Date: Mon, 31 May 1999 14:04:50 +0400 (MSD)
From: "Alex P. Rudnev" <alex@Relcom.EU.net>
To: Jessica Yu <jyy@ans.net>
Cc: Jessica Yu <jyy@ans.net>, Alex Zinin <zinin@amt.ru>,
Vadim Antonov <avg@kotovnik.com>, nanog@merit.edu
In-Reply-To: <199905282016.QAA11470@cannes.aa.ans.net>
Errors-To: owner-nanog-outgoing@merit.edu
>
> I was talking about ISP network which mostly is leased-line based.
> It depends on link stability and router stability. As I pointed out
> in my previous message, the more router and link a network has (i.e.
> the large scaled network), the large chance of having link flapping
> and router crashes (if you think in percentage sense), the more flooding,
> SPF calculation and LSDB update all routers in the network have to
> handle. If there is a hierarchy, then only a portion of routers (not all
> the routers) would need to handle flooding, SPF calculation and LSDB update.
You are 100% right - it's the classic.
Through the initial question whas _does we need hierarchical multi-level
SPF routing schema?_. And my opinion was _yes, but due to administration,
but not CPU/memory issues (yes, this is important too but it's
importance is usially overestimated).
And no one from this list argued for this hierarchy at all.
>
> Also, the large the size of network (lots of routers and links), the
> bigger the LSDB and the higher complexity of SPF calculation.
>
> --Jessica
>
>
>
Aleksei Roudnev, Network Operations Center, Relcom, Moscow
(+7 095) 194-19-95 (Network Operations Center Hot Line),(+7 095) 230-41-41, N 13729 (pager)
(+7 095) 196-72-12 (Support), (+7 095) 194-33-28 (Fax)
