Routing
Routing

ibgp and route reflector

‎08-07-2016 04:47 AM

Hi Guys

 

I am seeking your kind advice for some topology that i am doing in a lab.
Below i s the drawing of the lab.

 

123.jpg

 

There is 2 RR, called RR1 and RR2, and RRC1 and RRC2. RR1 is having an ibgp to RR2.

RRC1 has a cluster of 11.11.11.11 while RRC2 has a cluster of 22.22.22.22 towards RR1.

RRC1 has a cluster of 11.11.11.11 while RRC2 has a cluster of 22.22.22.22 towards RR2.

 

RR1> show bgp summary | match 100
1.1.1.2                 100        797        798       0       2     6:03:39 3/3/3/0              0/0/0/0
2.2.2.2                 100        793        798       0       4     6:03:20 0/3/3/0              0/0/0/0
100.1.1.2               100        816        814       0       8     6:08:30 0/0/0/0              0/0/0/0

 

RR2> show bgp summary | match 100
1.1.1.2                 100        798        800       0       8     6:03:20 3/3/3/0              0/0/0/0
2.2.2.2                 100        794        800       0       8     6:03:01 0/3/3/0              0/0/0/0
100.1.1.1               100        870        874       0       1     6:08:11 5/5/5/0              0/0/0/0

 

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RRC1#sh ip bgp neighbors 100.1.1.1 advertised-routes
BGP table version is 4, local router ID is 5.5.5.5
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, x best-external, f RT-Filter
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 20.2.0.0/16      0.0.0.0                  0         32768 i
*> 20.3.0.0/16      0.0.0.0                  0         32768 i
*> 20.4.0.0/16      0.0.0.0                  0         32768 i

Total number of prefixes 3

 

RRC2#sh ip bgp neighbors 100.1.1.1 advertised-routes
BGP table version is 4, local router ID is 6.6.6.6
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *>  20.2.0.0/16      0.0.0.0                  0         32768 i
 *>  20.3.0.0/16      0.0.0.0                  0         32768 i
 *>  20.4.0.0/16      0.0.0.0                  0         32768 i

Total number of prefixes 3

 

----------------------------------------------------------------------------------------------------------------------------------------------------------------

 

RRC1#sh ip bgp neighbors 100.1.1.2 advertised-routes
BGP table version is 4, local router ID is 5.5.5.5
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, x best-external, f RT-Filter
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 20.2.0.0/16      0.0.0.0                  0         32768 i
*> 20.3.0.0/16      0.0.0.0                  0         32768 i
*> 20.4.0.0/16      0.0.0.0                  0         32768 i

Total number of prefixes 3

RRC2#sh ip bgp neighbors 100.1.1.2 advertised-routes
BGP table version is 4, local router ID is 6.6.6.6
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *>  20.2.0.0/16      0.0.0.0                  0         32768 i
 *>  20.3.0.0/16      0.0.0.0                  0         32768 i
 *>  20.4.0.0/16      0.0.0.0                  0         32768 i

Total number of prefixes 3

 

 

i can receive the route from both of the RRC towards the RR1 and RR2

 

RR1> show route receive-protocol bgp 1.1.1.2

inet.0: 107 destinations, 120 routes (104 active, 0 holddown, 3 hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
* 20.2.0.0/16             1.1.1.2              0       100        I
* 20.3.0.0/16             1.1.1.2              0       100        I
* 20.4.0.0/16             1.1.1.2              0       100        I

iso.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)

inet6.0: 42 destinations, 46 routes (42 active, 0 holddown, 0 hidden)

{master}


RR1> show route receive-protocol bgp 2.2.2.2   

inet.0: 107 destinations, 120 routes (104 active, 0 holddown, 3 hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
  20.2.0.0/16             2.2.2.2              0       100        I
  20.3.0.0/16             2.2.2.2              0       100        I
  20.4.0.0/16             2.2.2.2              0       100        I

iso.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)

inet6.0: 42 destinations, 46 routes (42 active, 0 holddown, 0 hidden)

 

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RR2> show route receive-protocol bgp 1.1.1.2

inet.0: 91 destinations, 107 routes (89 active, 0 holddown, 2 hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
* 20.2.0.0/16             1.1.1.2              0       100        I
* 20.3.0.0/16             1.1.1.2              0       100        I
* 20.4.0.0/16             1.1.1.2              0       100        I

iso.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)

inet6.0: 19 destinations, 19 routes (19 active, 0 holddown, 0 hidden)

 

RR2> show route receive-protocol bgp 2.2.2.2   

inet.0: 91 destinations, 107 routes (89 active, 0 holddown, 2 hidden)
  Prefix                  Nexthop              MED     Lclpref    AS path
  20.2.0.0/16             2.2.2.2              0       100        I
  20.3.0.0/16             2.2.2.2              0       100        I
  20.4.0.0/16             2.2.2.2              0       100        I

iso.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)

inet6.0: 19 destinations, 19 routes (19 active, 0 holddown, 0 hidden)

 

----------------------------------------------------------------------------------------------------------------------------------------------------------------

 

From the route receive from both my RRC i can announce this to my ibgp neighbor from RR1 to RR2 with the cluster and originator appended

 

RR1> show route advertising-protocol bgp 100.1.1.2 20.2.0.0 active-path detail

inet.0: 107 destinations, 120 routes (104 active, 0 holddown, 3 hidden)
* 20.2.0.0/16 (2 entries, 1 announced)
 BGP group IBGP-RR type Internal
     Nexthop: 1.1.1.2
     MED: 0
     Localpref: 100
     AS path: [100] I
     Cluster ID: 11.11.11.11
     Originator ID: 5.5.5.5
 

---------------------------------------------------------------------------------------------------------------------------------------------------------------

 

However in RR2 i am not receiving this route

 

RR2> show route receive-protocol bgp 100.1.1.1 20.2.0.0

inet.0: 91 destinations, 107 routes (89 active, 0 holddown, 2 hidden)

RR2>

 

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The route 20.2.0.0/16 in RR2 is learnt via RRC1 and RRC2 instead from RR1,is there any loop mechanism where it detects the same originator_id, drops it and receive only one of the route based on bgp path selection ? i am rather confused, i thought RR2 should have 3 bgp path if i use the detail command, from RRC1, RRC2 and from RR1, and then use the path selection to use the best route and foward the traffic out

 

RR1> show route 20.2.0.0 detail

inet.0: 107 destinations, 120 routes (104 active, 0 holddown, 3 hidden)
20.2.0.0/16 (2 entries, 1 announced)
        *BGP    Preference: 170/-101
                Next hop type: Indirect
                Address: 0x92b9e58
                Next-hop reference count: 9
                Source: 1.1.1.2
                Next hop type: Router, Next hop index: 1100
                Next hop: 1.1.1.2 via ge-2/3/5.0, selected
                Session Id: 0x21b
                Protocol next hop: 1.1.1.2
                Indirect next hop: 95a8000 1048574 INH Session ID: 0x220
                State: <Active Int Ext>
                Local AS:   200 Peer AS:   100
                Age: 13:34      Metric: 0       Metric2: 0
                Validation State: unverified
                Task: BGP_100_100.1.1.1.2+46007
                Announcement bits (4): 0-KRT 3-RT 8-BGP_RT_Background 9-Resolve tree 4
                AS path: I
                AS path: Recorded
                Accepted
                Localpref: 100
                Router ID: 5.5.5.5
         BGP    Preference: 170/-101
                Next hop type: Indirect
                Address: 0x92ba610
                Next-hop reference count: 3
                Source: 2.2.2.2
                Next hop type: Router, Next hop index: 1611
                Next hop: 100.1.1.35 via ge-1/2/1.0, selected
                Session Id: 0x20d
                Protocol next hop: 2.2.2.2
                Indirect next hop: 95a80ec - INH Session ID: 0x0
                State: <NotBest Int Ext>
                Inactive reason: Not Best in its group - Router ID
                Local AS:   200 Peer AS:   100
                Age: 12:50      Metric: 0       Metric2: 0
                Validation State: unverified
                Task: BGP_100_100.2.2.2.2+57459
                AS path: I
                AS path: Recorded
                Accepted
                Localpref: 100
                Router ID: 6.6.6.6

    
------------------------------------------------------------------------------

RR2> show route 20.2.0.0 detail

inet.0: 91 destinations, 107 routes (89 active, 0 holddown, 2 hidden)
20.2.0.0/16 (2 entries, 1 announced)
        *BGP    Preference: 170/-101
                Next hop type: Indirect
                Address: 0x92b63b0
                Next-hop reference count: 9
                Source: 1.1.1.2
                Next hop type: Router, Next hop index: 691
                Next hop: 100.1.1.34 via ge-1/2/1.0, selected
                Session Id: 0x37945
                Protocol next hop: 1.1.1.2
                Indirect next hop: 9538000 1048574 INH Session ID: 0x37d23
                State: <Active Int Ext>
                Local AS:   100 Peer AS:   100
                Age: 13:23      Metric: 0       Metric2: 0
                Validation State: unverified
                Task: BGP_100.1.1.1.2+14793
                Announcement bits (4): 0-KRT 2-RT 8-BGP_RT_Background 9-Resolve tree 4
                AS path: I
                AS path: Recorded
                Accepted
                Localpref: 100
                Router ID: 5.5.5.5
         BGP    Preference: 170/-101
                Next hop type: Indirect
                Address: 0x92b5b60
                Next-hop reference count: 3
                Source: 2.2.2.2
                Next hop type: Router
                Next hop: 2.2.2.2 via ge-1/3/5.0, selected
                Session Id: 0x0
                Protocol next hop: 2.2.2.2
                Indirect next hop: 95380ec - INH Session ID: 0x0
                State: <Int Ext>
                Inactive reason: Router ID
                Local AS:   100 Peer AS:   100
                Age: 12:39      Metric: 0       Metric2: 0
                Validation State: unverified
                Task: BGP_100.2.2.2.2+31649
                AS path: I
                AS path: Recorded
                Accepted
                Localpref: 100
                Router ID: 6.6.6.6    

 

 

4 REPLIES 4
Routing

Re: ibgp and route reflector

‎08-07-2016 07:19 AM

It seems you are confused about where to configure the cluster-id. The cluster-id has to be configured on the route reflector not on the clients. From a configuration point of view, a client does not know whether it is part of a route reflector client or not.

 

Cheers,

Carsten

Routing

Re: ibgp and route reflector

‎08-07-2016 08:04 AM

 

the cluster-id is configured at the router reflector, the cisco is just a client of the juniper.

 

Routing

Re: ibgp and route reflector

‎08-07-2016 08:23 AM

I beleive RR1 and RR2 are  non-client  to each other ..

 

In RR2 ,Can you configure "keep all " knob under neighbor stanza for the neighbor RR1

[edit protocols bgp group group-name neighbor 100.1.1.1]

 

 

and paste the  "show route receive-protocol bgp 100.1.1.1 20.2.0.0" o/p again.

 

 

Routing

Re: ibgp and route reflector

[ Edited ]
‎08-07-2016 03:13 PM

HI,

 

I didn't quite understand from the picture which are RRC1 & RRC2 but assume they are the red routers.

Also assume that RR1 & RR2 are configured with the cluster IDs to be acting as RRs.  Otherwise, an iBGP route will not be re-advertised to another iBGP peer unless if a RR. This statement creates a bit of confusion though:

__________________________________________________________________________

RRC1 has a cluster of 11.11.11.11 while RRC2 has a cluster of 22.22.22.22 towards RR1.

RRC1 has a cluster of 11.11.11.11 while RRC2 has a cluster of 22.22.22.22 towards RR2.

__________________________________________________________________________

It might be helpful if you could share your configuration for better understanding.

 

If the route is being advertised to RR2 from RR1, I believe it should have been received by RR2. I would also expect to see 3 BGP paths and after the decision for best path then an active path computed [default behavior].

Could you check for:

show route receive-protocol bgp 100.1.1.1 hidden | extensive

Also, I noted iBGP peering is configured with the interface IP addresses. The best practice to use loopback IPs for the iBGP peering.

 

Cheers,

Ashvin