[j-nsp] BGP multipath trouble.

["Krasimir Avramski"]

To disable the default check requiring that paths accepted by BGP multipath must
have the same neighboring AS, include the multiple-as option:

multipath {
multiple-as;

Unfortunately this option not available in 6.4.



> This is unavailable option in 6.4 :( And it's undesirable for me to
> enable it on router, where load-balancing is required only for 2 peers
> (with more than 200 existing), because it can cause consistent
> unnecessary best path transitions.
> 
> > Try configuring external-router-id:
> >
> > http://www.juniper.net/techpubs/software/junos/junos76/swconfig76-routin
> > g/html/bgp-summary42.html
> >
> > HTHs
> >
> >
> >
> >> -----Original Message-----
> >> From: juniper-nsp-bounces at puck.nether.net
> >> [mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of
> >> Vladimir S. Blazhkun
> >> Sent: Tuesday, August 15, 2006 12:18 PM
> >> To: juniper-nsp at puck.nether.net
> >> Subject: [j-nsp] BGP multipath trouble.
> >>
> >>
> >> Hello, i have a trouble with load-balancing traffic to the
> >> same prefix, with the same AS_PATH, and other metrics. I have
> >> 2 upstream connections to different ASes, see all required
> >> outputs below. Both next-hops are not installed for
> >> forwarding traffic (seems first one is preferred due
> >> implementation of draft-ietf-idr-avoid-transition). Are there
> >> any workarounds for this in JUNOS 6.4?
> >>
> >> # show protocols bgp group UPstream-peers
> >>
> >> type external;
> >> graceful-restart {
> >>      disable;
> >> }
> >> multipath;
> >> neighbor XXX.XXX.0.125 {
> >>      passive;
> >>      import [ remove-private-as remove-bogus-nets
> >> long-prefixes flap-damping UPstream-XXXXX-Import ];
> >>      export UPstream-XXXXX-Announce;
> >>      peer-as XX16;
> >> }
> >> neighbor XXX.XXX.99.45 {
> >>      passive;
> >>      import [ remove-private-as remove-bogus-nets
> >> long-prefixes flap-damping UPstream-XXXXXXXXXXX-Import ];
> >>      export UPstream-XXXXXXXXXXX-Announce;
> >>      peer-as XX99;
> >> }
> >>
> >> # run show route forwarding-table destination 4/8
> >>
> >> Routing table: inet
> >> Internet:
> >> Destination        Type RtRef Next hop           Type Index
> >> NhRef Netif
> >> 4.0.0.0/8          user     0                    indr   603 13757
> >>                                XXX.XXX.0.125      ucst   589
> >>    3 fe-0/3/1.104
> >>
> >> # run show route 4/8 exact detail
> >>
> >> 4.0.0.0/8 (2 entries, 1 announced)
> >>          *BGP    Preference: 170/-101
> >>                  Next-hop reference count: 219519
> >>                  Source: XXX.XXX.0.125
> >>                  Next hop: XXX.XXX.0.125 via fe-0/3/1.104, selected
> >>                  Protocol next hop: XXX.XXX.0.125 Indirect
> >> next hop: 863a700 603
> >>                  State: 
> >>                  Local AS: XXXXX Peer AS:  XX16
> >>                  Age: 2:48:29    Metric: 200     Metric2: 0
> >>                  Task: BGP_XX16.XXX.XXX.0.125+26165
> >>                  Announcement bits (3): 0-KRT
> >> 4-BGP.0.0.0.0+179 5-Resolve inet.0
> >>                  AS path: XX16 3356 I (Atomic) Aggregator:
> >> 3356 4.69.130.2
> >>                  Communities: 3356:0 3356:3 3356:100 3356:123
> >> 3356:575 3356:2011
> >>                  Localpref: 100
> >>                  Router ID: XXX.XX.0.216
> >>           BGP    Preference: 170/-101
> >>                  Next-hop reference count: 542310
> >>                  Source: XXX.XXX.99.45
> >>                  Next hop: XXX.XXX.99.45 via fe-0/3/1.105, selected
> >>                  Protocol next hop: XXX.XXX.99.45 Indirect
> >> next hop: 863a400 587
> >>                  State: 
> >>               !! ->> Inactive reason: Active preferred
> >>                  Local AS: XXXXX Peer AS:  XX99
> >>                  Age: 2:47:18    Metric: 200     Metric2: 0
> >>                  Task: BGP_XX99.XXX.XXX.99.45+17205
> >>                  AS path: XX99 3356 I (Atomic) Aggregator:
> >> 3356 4.69.130.10
> >>                  Communities:
> >>                  Localpref: 100
> >>                  Router ID: XX.XXX.146.98
> 
> --
> Vladimir S. Blazhkun,
> JNSS-M JNCIA-M #773 JNCIS-M #1100 JNCIP-M #289 JNCI-M
> JNCIA-J JNCI-J
> _______________________________________________
> juniper-nsp mailing list juniper-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/juniper-nsp
> 
> 


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