[j-nsp] Juniper BGP Route Metrics

[Dan Benson]

Correct, I am currently using inet.3 for my IBGP next-hop loop addresses 
and therein lies my issue.  Let me take one second and try and 
re-explain my network and what I see my issue as.  I have a national 
network all based on junipers running OSPF, LDP, MPLS and BGP (I and E 
as one would assume). Here is the long and short of my issue. 

I learn the same prefix paths from neighboring AS's where I peer and or 
buy connectivity across the country.  I would like to send my traffic to 
the most local interconnect point when sending outbound traffic from my 
AS.   In my network currently  I show on certain prefixes the same AS 
hop count, Metric and Metric2 for my path choices unless I receive a MED 
from a peer.  This leaves my routers to fall to the router-id for the 
path selection which causes my traffic to flow to the wrong interconnect 
for my outbound traffic adding time to my traffic.

I am running LDP on every core router currently tracking IGP and I have 
no issue with this.  I do in my eyes have issue with not being able to 
have my BGP path selection use some form of metric toggle that comes 
from my IGP. At this point the only thing I have been able to do to 
achieve my desired traffic flow is to manually set the neighbor 
preference with a hierarchy based on physical distance from core router 
to core router.  This will be impossible to maintain in a full mesh and 
I think it is a band aid that I do not want to implement. I hope this 
helps with your in-site and I cannot thank you all enough for the help..

The same Prefix paths as before but with more explanation:

>From my LAX-2 Non-Edge router:

show route protocol bgp 155.212.0.0 detail (Random subnet learned from a 
peer AS):

inet.0: 217037 destinations, 706742 routes (217035 active, 2 holddown, 0 
hidden)
155.212.0.0/16 (3 entries, 1 announced)
       *BGP    Preference: 170/-91
               Next-hop reference count: 35478
               Source: 10.0.0.16
               Next hop: via at-0/0/0.0, selected
               Label operation: Push 198480
               Protocol next hop: 198.32.118.12
               Indirect next hop: 93403a8 262226
               State: <Active Int Ext>
               Local AS:  1784 Peer AS:  1784
               Age: 4d 14:15:14        Metric: 0       Metric2: 0
               Task: BGP_1784.10.0.0.16+2131
               Announcement bits (3): 0-KRT 5-RT 6-Resolve tree 2
               AS path: 174 14751 14751 14751 I ()
               Communities: 1784:1001
               Localpref: 90
               Router ID: 10.0.0.16
This source address is the loop of my edge router in NYC.

        BGP    Preference: 170/-91
               Next-hop reference count: 11931
               Source: 10.0.0.80
               Next hop: via at-0/0/0.0, selected
               Label operation: Push 198576
               Protocol next hop: 198.32.124.103
               Indirect next hop: 12734750 262165
               State: <Int Ext>
               Inactive reason: Router ID
               Local AS:  1784 Peer AS:  1784
               Age: 4d 14:15:31        Metric: 0       Metric2: 0
               Task: BGP_1784.10.0.0.80+179
               AS path: 174 14751 14751 14751 I ()
               Communities: 1784:1001
               Localpref: 90
               Router ID: 10.0.0.80
This source address is the loop of my edge router in Miami.


        BGP    Preference: 170/-91
               Next-hop reference count: 11682
               Source: 10.0.0.113
               Next hop: via at-0/0/0.0, selected
               Protocol next hop: 198.32.176.131
               Indirect next hop: 9340444 262289
               State: <Int Ext>
               Inactive reason: Router ID
               Local AS:  1784 Peer AS:  1784
               Age: 4d 14:14:59        Metric: 0       Metric2: 0
               Task: BGP_1784.10.0.0.113+3209
               AS path: 174 14751 14751 14751 I ()
               Communities: 1784:1001
               Localpref: 90
               Router ID: 10.0.0113

This source address is the loop of my edge router in LAX, about half a MilliSec from this router itself.  This is the path that would have been preferred before I implemented MPLS as the packet would traverse this edge router itself and be forwarded toward the peer. Thanks again.. //db


Sergio D. wrote:
> Krasi,
> protocol next-hop uses inet.3 by default.
>
> Dan,
> Can you give us a show route extensive for each protocol next-hop?
>
> Thanks,
> -- 
> Sergio Danellli
> JNCIE #170
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