Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

Exercise 3Routing Filters and Policies


Step 1Add AS Path



show bgp


Code Block
titleprepend 200 200 200 200
collapsetrue
admin@node2.bosdc1# show bgp 
Thu 2021-05-06 20:55:10 UTC
BGP table version is 12, local router ID is 3.3.3.128, vrf id 0
Status codes:  s suppressed, d damped, h history, * valid, > best, = multipath,
               i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes:  i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 1.1.1.0/24       3.3.3.1                  0             0 6000 i
*> 2.2.2.0/24       3.3.3.1                  0             0 200 200 200 200 6000 i
*> 3.3.3.0/24       3.3.3.1                  0             0 6000 i
*> 128.128.128.1/32 0.0.0.0            1000000         32768 ?
*> 128.128.128.128/32
                    0.0.0.0            1000000         32768 ?
*> 172.26.128.0/30  0.0.0.0                  0         32768 i

Displayed  6 routes and 6 total paths


Completed in 0.16 seconds
admin@node2.bosdc1# 


Step 2Add Community String

1- Create a Filter

2- Policy

2a- Condition

2b- Actions

SSR


Code Block
titleshow bgp router
collapsetrue
admin@node1.nycconductor1# show bgp router all 172.26.128.0
Thu 2021-05-06 21:05:58 UTC
WARNING: Targeting router 'all' may take a long time. Continue anyway? [y/N]: y
========
 bosdc1
========
BGP routing table entry for 172.26.128.0/30
Paths: (1 available, best #1, table Default-IP-Routing-Table)
  Advertised to non peer-group peers:
  3.3.3.1
  Local
    0.0.0.0 from 0.0.0.0 (3.3.3.128)
      Origin IGP, metric 0, localpref 100, weight 32768, valid, sourced, local, best
      Community: 128:128
      AddPath ID: RX 0, TX 11
      Last update: Thu May  6 21:05:08 2021



on FRR

show bgp ipv4 172.26.128.0/30


Code Block
titleshow bgp <route> on FRRouting
collapsetrue
internet-router# show bgp ipv4 172.26.128.0/30
BGP routing table entry for 172.26.128.0/30
Paths: (1 available, best #1, table Default-IP-Routing-Table)
  Advertised to non peer-group peers:
  1.1.1.128 2.2.2.128 3.3.3.128
  300
    3.3.3.128 from 3.3.3.128 (3.3.3.128)
      Origin IGP, metric 0, localpref 100, valid, external, best
      Community: 128:128
      AddPath ID: RX 0, TX 8
      Last update: Thu May  6 21:05:29 2021

internet-router# 


Step 3Reject Community String






...