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| Visual Objective for Lab 1-2 |
Note: The current topology is a portion from the main topology in my first blog. (BGP Initial Setup)
Task 1: Configuring BGP
Procedure:
- Start the process on WG1R1, use AS 1, peering with router Good in AS 20
- Announce the IP prefixes 197.1.0.0 /16 (classless), 192.168.1.0 /24 (classful)
- Ensure that WG1R1 is the exit point for your pod and is originating a default route for your IGP (OSPF)
Procedures 1 - 3
from WG1R1:
router bgp 1 ---------- WG1R1 will be peering with Good using AS 1
no synchronization
bgp log-neighbor-changes
network 192.168.1.0 ----------------------------- Step 2 (classful) no mask needed
network 197.1.0.0 mask 255.255.0.0 --------- Step 2 (classless)
neighbor 192.168.20.20 remote-as 20 -------- Good
no auto-summary
ip route 197.1.0.0 255.255.0.0 Null0 250 - this static route will provide the exact route and allow BGP to advertise our classless network.
Note: The WG1R1 router loopback 0 and 1 is configured with ip address 197.1.1.0 /24 and 197.1.8.0 /24. Configuring the command network 197.1.0.0 mask 255.255.0.0 is still not sufficient for our router to advertise the 2 networks. There will be no exact route for 197.1.0.0 /16 in the routing table. Configuring a static route will fix the issue. You can find more explanation here:
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800945ff.shtml
router ospf 1
default-information originate always ------ this command will allow OSPF to generate the default route. You can find more explanation here:
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094a74.shtml
Verify that you have established a BGP session.
BGP router identifier 197.1.8.1, local AS number 1
BGP table version is 25, main routing table version 25
24 network entries using 2808 bytes of memory
24 path entries using 1248 bytes of memory
10/9 BGP path/bestpath attribute entries using 1240 bytes of memory
8 BGP AS-PATH entries using 192 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 5488 total bytes of memory
BGP activity 24/0 prefixes, 24/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
192.168.20.20 4 20 618 367 25 0 0 00:10:06 23
WG1R1#show ip bgp neighbor 192.168.20.20
BGP neighbor is 192.168.20.20, remote AS 20, external link
BGP version 4, remote router ID 199.199.199.199
BGP state = Established, up for 00:57:11
Last read 00:00:01, last write 00:00:01, hold time is 5, keepalive interval is 1 seconds
Neighbor capabilities:
Route refresh: advertised and received(old & new)
Address family IPv4 Unicast: advertised and received
Message statistics:
InQ depth is 0
OutQ depth is 0
Sent Rcvd
Opens: 1 1
Notifications: 0 0
Updates: 1 10
Keepalives: 2061 3432
Route Refresh: 0 0
Total: 2063 3443
Default minimum time between advertisement runs is 30 seconds
For address family: IPv4 Unicast
BGP table version 25, neighbor version 25/0
Output queue size : 0
Index 1, Offset 0, Mask 0x2
1 update-group member
Sent Rcvd
Prefix activity: ---- ----
Prefixes Current: 1 23 (Consumes 1196 bytes)
Prefixes Total: 1 23
Implicit Withdraw: 0 0
Explicit Withdraw: 0 0
Used as bestpath: n/a 23
Used as multipath: n/a 0
Outbound Inbound
Local Policy Denied Prefixes: -------- -------
AS_PATH loop: n/a 1
Bestpath from this peer: 23 n/a
Total: 23 1
Number of NLRIs in the update sent: max 1, min 1
Connections established 1; dropped 0
Last reset never
Connection state is ESTAB, I/O status: 1, unread input bytes: 0
Connection is ECN Disabled, Mininum incoming TTL 0, Outgoing TTL 1
Local host: 192.168.20.1, Local port: 179
Foreign host: 192.168.20.20, Foreign port: 27458
Telnet router Good to verify if it is receiving the networks advertised by WG1R1
WG1R1#telnet good
Trying good (192.168.20.20)... Open
Good>en
Password:
Good#show ip bgp
BGP table version is 27, local router ID is 199.199.199.199
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
*> 197.1.0.0/16 192.168.20.1 0 0 1 i -------------------- this is the WG1R1 loobpack addresses
*> 200.20.0.0/16 0.0.0.0 0 32768 i
*> 200.22.0.0/16 192.168.20.22 0 0 22 i
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