Tuesday, 27 November 2018

BGP Peer Group and config


 By default,  BGP updates are sent on a neighbor to neighbor basis and the  result  more CPU resources being used, also by implementing  non-default settings  for example performing filtering using prefix lists, route map, or filter list to those neighbors, even more CPU resources are consume.

 When, many neighbors are having similar configuration parameters. Cisco IOS allows us to create logical group those similar neighbors into a BGP peer group then you apply your non-default BGP configuration to those parameters to each neighbor individually. Actually a single router can have multiple peer groups, each representing a separate set of parameters. The result less CPU resources required. Remember router still sends out individual BGP updates to each of its neighbors. It does require based on BGP characteristics of establishing a TCP session with each neighbor.


Inshort: BGP peer group means applying same policies to multiple neighbors.It's useful when many neighbors have the same configuration parameter. updates are generated once per peer group.






lets see the configurations.
Topology:

Goal:



  • configure the topology as per the diagram and its interfaces.
  • configure eigrp 100 all the routers to ensure the reachability between the loopbacks. 
  • configure loopback 0 to establishing peering, configure peer group name cisco.
  • configure authentication and make sure all the peer should use same password.(in our topology we use internetworks)
  • configure BGP version 4 and advertise LAN interfaces only.


R1#show ip interface brief
Interface              IP-Address      OK? Method Status                Protocol
FastEthernet0/0        10.1.1.1        YES manual up                    up
Serial3/0                     1.1.1.1         YES manual up                    up
Serial3/3                     4.1.1.2         YES manual up                    up
Loopback0              11.0.0.1        YES manual up                    up
Loopback1              11.0.1.1        YES manual up                    up
Loopback2              11.0.2.1        YES manual up                    up
Loopback3              11.0.3.1        YES manual up                    up


R2#show ip interface brief
Interface              IP-Address      OK? Method Status                Protocol
FastEthernet0/0        20.1.1.1        YES manual up                    up
Serial3/0                     1.1.1.2         YES manual up                    up
Serial3/1                     2.1.1.1         YES manual up                    up
Loopback0              12.0.0.1        YES manual up                    up
Loopback1              12.0.1.1        YES manual up                    up
Loopback2              12.0.2.1        YES manual up                    up

Loopback3              12.0.3.1        YES manual up                    up



R3#show ip interface brief
Interface              IP-Address      OK? Method Status                Protocol
FastEthernet0/0        30.1.1.1        YES manual up                    up
Serial3/1                   2.1.1.2         YES manual up                    up
Serial3/2                   3.1.1.1         YES manual up                    up
Loopback0              13.0.0.1        YES manual up                    up
Loopback1              13.0.1.1        YES manual up                    up
Loopback2              13.0.2.1        YES manual up                    up

Loopback3              13.0.3.1        YES manual up                    up



R4#show ip interface brief
Interface              IP-Address      OK? Method Status                Protocol
FastEthernet0/0        40.1.1.1        YES manual up                    up
Serial3/2                     3.1.1.2         YES manual up                    up
Serial3/3                     4.1.1.1         YES manual up                    up
Loopback0              14.0.0.1        YES manual up                    up
Loopback1              14.0.1.1        YES manual up                    up
Loopback2              14.0.2.1        YES manual up                    up

Loopback3              14.0.3.1        YES manual up                    up

R1(config)#router eigrp 100
R1(config-router)#network 10.0.0.0
R1(config-router)#network 1.0.0.0
R1(config-router)#network 4.0.0.0
R1(config-router)#network 11.0.0.0
R1(config-router)#no auto-summary
R1(config-router)#end


R2(config)#router eigrp 100
R2(config-router)#network 20.0.0.0
R2(config-router)#network 2.0.0.0
R2(config-router)#network 1.0.0.0
R2(config-router)#network 12.0.0.0
R2(config-router)#no auto-summary
R2(config-router)#end


R3(config)#router eigrp 100
R3(config-router)#network 13.0.0.0
R3(config-router)#network 2.0.0.0
R3(config-router)#network 3.0.0.0
R3(config-router)#network 30.0.0.0
R3(config-router)#no auto-summary
R3(config-router)#end


R4(config)#router eigrp 100
R4(config-router)#network 4.0.0.0
R4(config-router)#network 4.0.0.0
R4(config-router)#network 40.0.0.0
R4(config-router)#network 14.0.0.0
R4(config-router)#network 3.0.0.0
R4(config-router)#end



R1(config)#router bgp 501
R1(config-router)#neighbor cisco peer-group
R1(config-router)#neighbor cisco remote-as 501
R1(config-router)#neighbor cisco update-source loopback 0
R1(config-router)#neighbor cisco version 4
R1(config-router)#neighbor cisco password internetworks
R1(config-router)#neighbor 12.0.0.1 peer-group cisco
R1(config-router)#neighbor 13.0.0.1 peer-group cisco
R1(config-router)#neighbor 14.0.0.1 peer-group cisco
R1(config-router)#network 10.0.0.0
R1(config-router)#no auto-summary
R1(config-router)#no synchronization
R1(config-router)#end


R2(config)#router bgp 501
R2(config-router)#neighbor cisco peer-group
R2(config-router)#neighbor cisco remote-as 501
R2(config-router)#neighbor cisco update-source loopback 0
R2(config-router)#neighbor cisco version 4
R2(config-router)#neighbor cisco password internetworks
R2(config-router)#neighbor 11.0.0.1 peer-group cisco
R2(config-router)#neighbor 13.0.0.1 peer-group cisco
R2(config-router)#neighbor 14.0.0.1 peer-group cisco
R2(config-router)#network 20.0.0.0
R2(config-router)#no auto-summary
R2(config-router)#no synchronization
R2(config-router)#end


R3(config)#router bgp 501
R3(config-router)#neighbor cisco peer-group
R3(config-router)#neighbor cisco remote-as 501
R3(config-router)#neighbor cisco update-source loopback 0
R3(config-router)#neighbor cisco version 4
R3(config-router)#neighbor cisco password internetworks
R3(config-router)#neighbor 12.0.0.1 peer-group cisco
R3(config-router)#neighbor 11.0.0.1 peer-group cisco
R3(config-router)#neighbor 14.0.0.1 peer-group cisco
R3(config-router)#network 30.0.0.0
R3(config-router)#no auto-summary
R3(config-router)#no synchronization
R3(config-router)#end


R4(config)#router bgp 501
R4(config-router)#neighbor cisco peer-group 
R4(config-router)#neighbor cisco remote-as 501
R4(config-router)#neighbor cisco update-source loopback 0
R4(config-router)#neighbor cisco version 4
R4(config-router)#neighbor cisco  password internetworks
R4(config-router)#neighbor 12.0.0.1 peer-group cisco
R4(config-router)#neighbor 13.0.0.1 peer-group cisco
R4(config-router)#neighbor 11.0.0.1 peer-group cisco
R4(config-router)#network 40.0.0.0
R4(config-router)#no auto-summary
R4(config-router)#no synchronization
R4(config-router)#end


R1#show ip bgp summary
BGP router identifier 11.0.3.1, local AS number 501
BGP table version is 7, main routing table version 7
4 network entries using 576 bytes of memory
4 path entries using 320 bytes of memory
2/2 BGP path/bestpath attribute entries using 272 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1168 total bytes of memory
BGP activity 5/1 prefixes, 5/1 paths, scan interval 60 secs


Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
12.0.0.1        4          501       7       7        7    0    0 00:00:44        1
13.0.0.1        4          501      17      20        7    0    0 00:10:02        1

14.0.0.1        4          501       9       9        7    0    0 00:02:37        1


R2#show ip bgp summary
BGP router identifier 12.0.3.1, local AS number 501
BGP table version is 9, main routing table version 9
4 network entries using 576 bytes of memory
4 path entries using 320 bytes of memory
2/2 BGP path/bestpath attribute entries using 272 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1168 total bytes of memory
BGP activity 4/0 prefixes, 6/2 paths, scan interval 60 secs


Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
11.0.0.1        4          501       8       8        9    0    0 00:01:23        1
13.0.0.1        4          501       8       8        9    0    0 00:01:26        1
14.0.0.1        4          501       8       6        9    0    0 00:01:32        1


R3#show ip bgp summary
BGP router identifier 13.0.3.1, local AS number 501
BGP table version is 7, main routing table version 7
4 network entries using 576 bytes of memory
4 path entries using 320 bytes of memory
2/2 BGP path/bestpath attribute entries using 272 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1168 total bytes of memory
BGP activity 5/1 prefixes, 5/1 paths, scan interval 60 secs


Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
11.0.0.1        4          501      21      19        7    0    0 00:11:15        1
12.0.0.1        4          501       9       9        7    0    0 00:02:00        1
14.0.0.1        4          501       9      11        7    0    0 00:03:56        1


R4#show ip bgp summary
BGP router identifier 14.0.3.1, local AS number 501
BGP table version is 5, main routing table version 5
4 network entries using 576 bytes of memory
4 path entries using 320 bytes of memory
2/2 BGP path/bestpath attribute entries using 272 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1168 total bytes of memory
BGP activity 4/0 prefixes, 4/0 paths, scan interval 60 secs


Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
11.0.0.1        4          501      11      12        5    0    0 00:04:24        1
12.0.0.1        4          501       7       9        5    0    0 00:02:40        1
13.0.0.1        4          501      11       9        5    0    0 00:04:29        1


R1#show ip bgp
BGP table version is 7, local router ID is 11.0.3.1
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
 *>  10.0.0.0         0.0.0.0                  0         32768 i
 r>i 20.0.0.0         12.0.0.1                 0    100      0 i
 r>i 30.0.0.0         13.0.0.1                 0    100      0 i
 r>i 40.0.0.0         14.0.0.1                 0    100      0 i


R3#show ip bgp
BGP table version is 7, local router ID is 13.0.3.1
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
 r>i 10.0.0.0         11.0.0.1                 0    100      0 i
 r>i 20.0.0.0         12.0.0.1                 0    100      0 i
 *>  30.0.0.0         0.0.0.0                  0         32768 i
 r>i 40.0.0.0         14.0.0.1                 0    100      0 i
R1#show processes cpu history




                                   11111
      111122222111111111111111333330000044444666663333311111222225
  100
   90
   80
   70
   60
   50
   40
   30
   20
   10                              *****     *****
     0....5....1....1....2....2....3....3....4....4....5....5....6
               0    5    0    5    0    5    0    5    0    5    0
               CPU% per second (last 60 seconds)





      1                           1                      3
      024436222553333343433323324419263322223223312322262433222322
  100
   90
   80
   70
   60
   50
   40
   30                                                    *
   20                                                    *
   10 *    *   **                 ** *                 * #
     0....5....1....1....2....2....3....3....4....4....5....5....6
               0    5    0    5    0    5    0    5    0    5    0
               CPU% per minute (last 60 minutes)
              * = maximum CPU%   # = average CPU%





      31
      42
  100
   90
   80
   70
   60
   50
   40
   30 *
   20 *
   10 **
     0....5....1....1....2....2....3....3....4....4....5....5....6....6....7..
               0    5    0    5    0    5    0    5    0    5    0    5    0
                   CPU% per hour (last 72 hours)
                  * = maximum CPU%   # = average CPU%






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