[j-nsp] load balancing between multiple BGP links

[Guy Davies]

Of course :-(  Long week (already!).  Need to think more before blurting
out an answer ;-)

Rgds,

Guy 

>-----Original Message-----
>From: Harry Reynolds [mailto:harry at juniper.net] 
>Sent: 14 September 2005 14:49
>To: Alok; Guy Davies; Joe Shen; juniper-nsp at puck.nether.net
>Cc: cisco-nsp at puck.nether.net
>Subject: RE: [j-nsp] load balancing between multiple BGP links
>
>The link bandwidth community, as of 5.6, should balance accordingly:
>
>
>http://www.juniper.net/techpubs/software/junos/junos56/rn-sw-56
/html/rn-
>sw-563.html#1130062
>
>BGP multipath link-bandwidth attribute--When per-packet load-balancing
>is enabled, you can specify bandwidth values resulting in unequally
>distributed traffic when you set up a community policy for BGP 
>multipath
>path selection. By default, when you use BGP multipath, the router
>distributes traffic equally among the several paths it calculates. To
>configure an unequal distribution, include the bandwidth attribute,
>specifying the local autonomous system and link bandwidth in bytes per
>second, at the [edit policy-options community name] hierarchy 
>level. The
>show route detail and show route forwarding-table commands display the
>new output. [Policy, Command Reference]  
>
>HTHs
>
>> -----Original Message-----
>> From: juniper-nsp-bounces at puck.nether.net 
>> [mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of Alok
>> Sent: Wednesday, September 14, 2005 6:08 AM
>> To: Guy Davies; Joe Shen; juniper-nsp at puck.nether.net
>> Cc: cisco-nsp at puck.nether.net
>> Subject: Re: [j-nsp] load balancing between multiple BGP links
>> 
>> 
>> ----- Original Message -----
>> From: "Guy Davies" <Guy.Davies at telindus.co.uk>
>> To: "Joe Shen" <sj_hznm at yahoo.com.cn>; <juniper-nsp at puck.nether.net>
>> Cc: <cisco-nsp at puck.nether.net>
>> Sent: Wednesday, September 14, 2005 4:20 PM
>> Subject: RE: [j-nsp] load balancing between multiple BGP links
>> 
>> 
>> > Hi Joe,
>> >
>> > It can't with the physical layout you described.  BGP 
>> selects one next-hop
>> as the best (and only one).  The only way to load share is to 
>> have two (or
>> more) parallel links between just two routers.  You then 
>> create a static
>> route on each end via each physical next-hop to the loopback 
>> on the far end
>> router.  Then, you setup an ebgp multihop session between the 
>> loopbacks on
>> the two routers.  That then uses IGP load sharing to balance 
>> traffic across
>> the two parallel links.
>> >
>> 
>> Anyone knows what to expect in this scenario?
>> 
>> R1===========R2
>> 
>> EBGP multihop between them over 2 links
>> link 1 =10Mbps
>> link 2 = 20 Mbps
>> 
>> total traffic = 25Mbps
>> 
>> Is there a way to ensure that link 1 doesnt get choked?
>> 
>> 
>> -thanks
>> Alok
>> 
>> 
>> 
>> _______________________________________________
>> juniper-nsp mailing list juniper-nsp at puck.nether.net
>> http://puck.nether.net/mailman/listinfo/juniper-nsp
>> 
>

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