Very interesting...
But to be more interesting, let say your first link is to UUNET,
and in order to add more bandwidth for the downstream
your second link is Donwstream only (via satellite - say for example- from
Sprint)
no transmit circuit available from you to Sprint.
In this case: Sprint must advertise and prepend your network to the rest of
Internet:
network1 prepend your AS
network2 prepend your AS
network3 prepend your AS
network4 prepend your AS
and there is no outbound balancing, since you are transmitting way only to
UUNET.
Is that true?
Rgds,
raf
-----Original Message-----
From: Brian <[EMAIL PROTECTED]>
To: whitaker <[EMAIL PROTECTED]>
Cc: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Date: Monday, October 30, 2000 11:44 AM
Subject: Re: BGP Challenge
>On Sun, 29 Oct 2000, whitaker wrote:
>
>> ok, so I'm trying to implement some BGP routing for the first time.
>> I've read through the advanced IP network design, Internet Routing
>> Architectures, the RFCs, and a couple other books on BGP. But as we
>> all know, none of this compares to good experience. So, before I
>> attempt to implement BGP in mission critical datacenter, I thought I'd
>> run it by the experts (that's you!) to make sure I'm understanding
>> this right.
>>
>> I have two 6509s, each connecting through hssi interface to seperate
SONET rings to separate providers. We basically run like an ASP, and have
several networks we're advertising. One of our provider's OC-12 ring is not
currently implented yet, but this shouldn't make any difference in the
configuration.
>>
>> So, here's my sample BGP config:
>>
>> ! 6509A
>> router bgp <My AS number>
>> no synchronization
>>
>> ! list networks to advertise
>> network <network1> mask 255.255.255.0
>> network <network2> mask 255.255.255.240
>>
>> ! define provider1 and second 6509 as neighbors
>> neighbor <Genuity ip address> remote-as 1
>> neighbor <ip address of 6509B> remote-as <My AS number>
>>
>> ! Add filter list to only advertise internal routes so that we don't
become transitive
>> neighbor <Genuity ip address> filter-list 10 out
>> ip as-path access-list 10 permit ^$
>
>Don't you want the filter list on Genuity as well?
>
>>
>> ! prepend my AS number to network that is on 6509B. This should help to
'load-balance' some.
>> access-list 1 permit <network3> 255.255.255.0
>> access-list 1 permit <network4> 255.255.255.0
>> neighbor <genuity ip address> route-map add_as out
>
>the line above goes under your "router bgp" config section.
>
>> route-map add_as permit 10
>> match ip address 1
>> set as-path prepend <My AS> <My AS>
>
>this is correct.
>
>>
>> -------------------------------------------------------
>> ! 6509B
>> router bgp <My AS number>
>> ! list networks to advertise
>> network <network3> mask 255.255.255.0
>> network <network4> mask 255.255.255.0
>>
>> ! define provider2 and first 6509 as neighbors
>> neighbor <Sprint ip address> remote-as <sprint AS number>
>> neighbor <ip address of 6509A> remote-as <my AS number>
>>
>> ! Add filter list to only advertise internal routes so that we don't
become transitive
>> neighbor <Sprint ip address> filter-list 10 out
>> ip as-path access-list 10 permit ^$
>>
>> ! prepend my AS number to networks that are on 6509A. This should help to
'load-balance' some.
>> access-list 1 permit <network1> mask 255.255.255.0
>> access-list 1 permit <network2> mask 255.255.255.240
>> neighbor <sprint ip address> route-map add_as out
>> route-map add_as permit 10
>> match ip address 1
>> set as-path prepend <My AS> <My AS>
>>
>
>ok this all looks fine.
>
>>
>> Here's my questions:
>> * Networks are going to be added once a week, not all at once. To add a
network, it is my understanding that I type 'clear
>> ip bgp * soft-reconfiguration outbound' to reset the bgp connection. Is
this correct?
>>
>> * Does this configuration effectively make my network non-transitive?
>
>well, personally, i put an incoming and outgoing access list on the
>interfaces themselves, to deny any ip's of mine "in" (from the
>internet) and only allow my ip's "out". I also use both distribute lists
>and filter lists..........sort of like two forms of birth control :)
>
>>
>> * I've read about peer groups - would this be an effective way of
maintaining the configuration between the two 6509s? Or
>> would it just be adding an additional level of complexity?
>
>the configs are simple enough I don't think peer groups are really
>necessary or would even buy you much.
>
>>
>> * Will this configuration help to balance out the traffic some across the
two 6509s?
>
>well, anything can happen here. You have to let it roll and see whats
>going on. Certainly its a workable config. Probably would need to do a
>little tweaking of as-prepending and setting of local pref on some AS's,
>but probably not much more than that.
>
>Brian
>
>
>-----------------------------------------------
>Brian Feeny, CCNP, CCDP [EMAIL PROTECTED]
>Network Administrator
>ShreveNet Inc. (ASN 11881)
>
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