Alex P. Rudnev
alex at Relcom.EU.net
Tue Sep 14 19:25:07 UTC 1999
First of all. I should apologize for this thread - seems it is one more
grinding of the well-known things. And I never opposed to you.
Second, it seems for me there is really a lack of the good books about
the INTERNET and it's routing. The book mentioned below (btw, the
author's name at the paper book is Bassam Halabi, and differ slightly
from the one at the CCO server) describe BGP brightly, but do not explain
HOW TO DESIGN SIMPLE single-homed customer's network; multi-homed
customer's network; non-transit ISP; transit ISP...
And then (It's more the request to those who write the books) there is a
lack of the books explaining _what for this protocol was designed_ and
_how to use it in the 90% cases_. Good example #1 - OSPF - all books
describe AREAS, STUB's, DEAD INTERVAL, etc etc - but the first idea of
OSPF was _to be very simple in the simple cases_. It causes the students
(I had a time to watch their attempts to do simple labs here) to write a
complex, 100 lines-at-the-size configs from the first minute they began
to type in something into the router, or write terrible _redistribute_,
_stub_ etc when this configs are not necessary at all. This resulted to
the myths about the _complexity_ or _unstability_ or _difficulty to
config_ etc etc...
BGP - the same problem. Halabi write the excellent book; but try to
configure the simple _multi-homed_ customer's network guided by this
tool? First of all, no one word about IGP backgrounding network; second,
no distinction between the _SIMPLE_ cases (when it's better to write
router bgp 1111
network 22.214.171.124 255.254.0.0
neig 126.96.36.199 remote-as 1112
ip route 188.8.131.52 255.254.0.0 Null0 254
and the complex cases when you should transit third-party BGP routes by
your multi-area backbones.
And it's amazing - we are talking (this days) about L2/L3 switching,
about MPLS, tagging etc etc - and we just have almost ready 2-level
network (IGP - IBGP), but withouth any attempting to use any packet
tagging. Think - edge router receive the packet, and find the appropriate
route in BGP table; this route reference to the BGP next hop (outgoing
edge router). Instead of the tagging this packet by this _NEXT HOP_
address (and marking it's CoQ and other attributes) it send it unchanged
to the next core router and the whole indentification repeats again...
and again... And then some folks cry _we can use ATM background instead
of IGP background_ and draw MPLS heap of comlexity...
Btw, if summ everything was saying here in nanog by this Sublect, we
could collect a good FAQ by this subject _how to build simple ISP
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)
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