In the below topology, Traffic is asymmetric as outgoing
taffic from R1 is going via R2 -> R5 ->R6 whereas
taffic from R1 is going via R2 -> R5 ->R6 whereas
Incoming traffic is coming from R6-> R4 ->R3->R1
To remove asymmetric routing, we need to manipulate the
incoming traffic. AS-Prepend to be done on R3 so that R6 will always prefer the
path from R5.
incoming traffic. AS-Prepend to be done on R3 so that R6 will always prefer the
path from R5.
R1:-
interface Loopback0
ip address 1.1.1.1
255.255.255.255
255.255.255.255
interface FastEthernet0/0
description ”
Connected to R2″
Connected to R2″
ip address
12.12.12.1 255.255.255.0
12.12.12.1 255.255.255.0
no shut
interface FastEthernet0/1
description ”
Connected to R3″
Connected to R3″
ip address
13.13.13.1 255.255.255.0
13.13.13.1 255.255.255.0
no shut
interface FastEthernet2/0
description ”
Connected to PC1″
Connected to PC1″
ip address
10.1.1.1 255.255.255.0
10.1.1.1 255.255.255.0
no shut
router bgp 1
no synchronization
bgp
log-neighbor-changes
log-neighbor-changes
network 10.1.1.0
mask 255.255.255.0
mask 255.255.255.0
neighbor 12.12.12.2
remote-as 1
remote-as 1
neighbor
13.13.13.3 remote-as 1
13.13.13.3 remote-as 1
R2:-
interface Loopback0
ip address 2.2.2.2
255.255.255.255
255.255.255.255
interface FastEthernet0/0
description ”
Connected to R1″
Connected to R1″
ip address
12.12.12.2 255.255.255.0
12.12.12.2 255.255.255.0
no shut
interface FastEthernet1/0
description ”
Connected to R5″
Connected to R5″
ip address
25.25.25.2 255.255.255.0
25.25.25.2 255.255.255.0
no shut
router bgp 1
no synchronization
bgp router-id
2.2.2.2
2.2.2.2
bgp
log-neighbor-changes
log-neighbor-changes
neighbor
12.12.12.1 remote-as 1
12.12.12.1 remote-as 1
neighbor
12.12.12.1 next-hop-self
12.12.12.1 next-hop-self
neighbor
25.25.25.5 remote-as 2
25.25.25.5 remote-as 2
R3:-
interface Loopback0
ip address 3.3.3.3
255.255.255.255
255.255.255.255
interface FastEthernet0/1
description ” Connected to R1″
ip address
13.13.13.3 255.255.255.0
13.13.13.3 255.255.255.0
no shut
interface FastEthernet1/0
description ” Connected to R4″
ip address
34.34.34.3 255.255.255.0
34.34.34.3 255.255.255.0
no shut
router bgp 1
no synchronization
bgp router-id
3.3.3.3
3.3.3.3
bgp
log-neighbor-changes
log-neighbor-changes
neighbor
13.13.13.1 remote-as 1
13.13.13.1 remote-as 1
neighbor
13.13.13.1 next-hop-self
13.13.13.1 next-hop-self
neighbor
34.34.34.4 remote-as 2
34.34.34.4 remote-as 2
no auto-summary
configured AS Prepend:-
router bgp 1
neighbor 34.34.34.4 route-map SET_AS out
route-map SET_AS permit 10
set as-path
prepend 1 1 1 1
prepend 1 1 1 1
R4:-
interface FastEthernet0/1
description ” Connected to R6″
ip address
46.46.46.4 255.255.255.0
46.46.46.4 255.255.255.0
no shut
interface FastEthernet1/0
description ” Connected to R3″
ip address
34.34.34.4 255.255.255.0
34.34.34.4 255.255.255.0
no shut
router bgp 2
no synchronization
bgp
log-neighbor-changes
log-neighbor-changes
neighbor
34.34.34.3 remote-as 1
34.34.34.3 remote-as 1
neighbor
46.46.46.6 remote-as 2
46.46.46.6 remote-as 2
neighbor
46.46.46.6 next-hop-self
46.46.46.6 next-hop-self
no auto-summary
R5:-
interface Loopback0
ip address 5.5.5.5
255.255.255.255
255.255.255.255
interface FastEthernet0/0
description ” Connected to R6″
ip address
56.56.56.5 255.255.255.0
56.56.56.5 255.255.255.0
no shut
interface FastEthernet1/0
description ” Connected to R2″
ip address
25.25.25.5 255.255.255.0
25.25.25.5 255.255.255.0
no shut
router bgp 2
no synchronization
bgp
log-neighbor-changes
log-neighbor-changes
neighbor
25.25.25.2 remote-as 1
25.25.25.2 remote-as 1
neighbor
56.56.56.6 remote-as 2
56.56.56.6 remote-as 2
neighbor
56.56.56.6 next-hop-self
56.56.56.6 next-hop-self
no auto-summary
R6:-
interface Loopback0
ip address 6.6.6.6
255.255.255.255
255.255.255.255
interface FastEthernet0/0
description ” Connected to R5″
ip address
56.56.56.6 255.255.255.0
56.56.56.6 255.255.255.0
no shut
interface FastEthernet0/1
description ” Connected to R4″
ip address
46.46.46.6 255.255.255.0
46.46.46.6 255.255.255.0
no shut
interface FastEthernet2/0
description ” Connected to PC2″
ip address
20.1.1.1 255.255.255.0
20.1.1.1 255.255.255.0
no shut
router bgp 2
no synchronization
bgp
log-neighbor-changes
log-neighbor-changes
network 20.1.1.0
mask 255.255.255.0
mask 255.255.255.0
neighbor
46.46.46.4 remote-as 2
46.46.46.4 remote-as 2
neighbor
56.56.56.5 remote-as 2
56.56.56.5 remote-as 2
no auto-summary
PC1:-
PC1> show ip
NAME :
PC1[1]
PC1[1]
IP/MASK :
10.1.1.10/24
10.1.1.10/24
GATEWAY :
10.1.1.1
10.1.1.1
DNS :
MAC : 00:50:79:66:68:00
LPORT : 10003
RHOST:PORT :
127.0.0.1:10002
127.0.0.1:10002
MTU: : 1500
PC2:-
PC2> show ip
NAME :
PC2[1]
PC2[1]
IP/MASK :
20.1.1.10/24
20.1.1.10/24
GATEWAY :
20.1.1.1
20.1.1.1
DNS :
MAC :
00:50:79:66:68:00
00:50:79:66:68:00
LPORT : 10003
RHOST:PORT :
127.0.0.1:10002
127.0.0.1:10002
MTU: : 1500
Verification:-
R1:-
Without AS Prepend:-
R1#sh ip route
Codes: L – local, C – connected, S – static, R – RIP, M –
mobile, B – BGP
mobile, B – BGP
D – EIGRP,
EX – EIGRP external, O – OSPF, IA – OSPF inter area
EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF
NSSA external type 1, N2 – OSPF NSSA external type 2
NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF
external type 1, E2 – OSPF external type 2
external type 1, E2 – OSPF external type 2
i – IS-IS,
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
ia – IS-IS
inter area, * – candidate default, U – per-user static route
inter area, * – candidate default, U – per-user static route
o – ODR, P – periodic downloaded static
route, H – NHRP
route, H – NHRP
+ –
replicated route, % – next hop override
replicated route, % – next hop override
Gateway of last resort is not set
1.0.0.0/32 is
subnetted, 1 subnets
subnetted, 1 subnets
C 1.1.1.1 is
directly connected, Loopback0
directly connected, Loopback0
10.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
10.1.1.0/24 is directly connected, FastEthernet2/0
10.1.1.0/24 is directly connected, FastEthernet2/0
L
10.1.1.1/32 is directly connected, FastEthernet2/0
10.1.1.1/32 is directly connected, FastEthernet2/0
12.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
12.12.12.0/24 is directly connected, FastEthernet0/0
12.12.12.0/24 is directly connected, FastEthernet0/0
L
12.12.12.1/32 is directly connected, FastEthernet0/0
12.12.12.1/32 is directly connected, FastEthernet0/0
13.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
13.13.13.0/24 is directly connected, FastEthernet0/1
13.13.13.0/24 is directly connected, FastEthernet0/1
L
13.13.13.1/32 is directly connected, FastEthernet0/1
13.13.13.1/32 is directly connected, FastEthernet0/1
20.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 20.1.1.0 [200/0] via 12.12.12.2,
00:10:52 //best path is selected as per selection criteria,
lowest router ID.
00:10:52 //best path is selected as per selection criteria,
lowest router ID.
R1#sh ip bgp summ
BGP router identifier 1.1.1.1, local AS number 1
BGP table version is 18, main routing table version 18
2 network entries using 256 bytes of memory
3 path entries using 156 bytes of memory
2/2 BGP path/bestpath attribute entries using 248 bytes
of memory
of memory
1 BGP AS-PATH entries using 24 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 684 total bytes of memory
BGP activity 3/1 prefixes, 9/6 paths, scan interval 60
secs
secs
Neighbor
V AS MsgRcvd
MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
V AS MsgRcvd
MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
12.12.12.2
4 1 84
83 18 0
0 01:11:37 1
4 1 84
83 18 0
0 01:11:37 1
13.13.13.3
4 1 192
187 18 0
0 02:47:10 1
4 1 192
187 18 0
0 02:47:10 1
R1#sh ip bgp neighbors | in router
BGP version 4,
remote router ID 2.2.2.2
remote router ID 2.2.2.2
BGP version 4,
remote router ID 3.3.3.3
remote router ID 3.3.3.3
R1#
With AS Prepend:-
R1#sh ip route
Codes: L – local, C – connected, S – static, R – RIP, M –
mobile, B – BGP
mobile, B – BGP
D – EIGRP,
EX – EIGRP external, O – OSPF, IA – OSPF inter area
EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF
NSSA external type 1, N2 – OSPF NSSA external type 2
NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF
external type 1, E2 – OSPF external type 2
external type 1, E2 – OSPF external type 2
i – IS-IS,
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
ia – IS-IS
inter area, * – candidate default, U – per-user static route
inter area, * – candidate default, U – per-user static route
o – ODR, P –
periodic downloaded static route, H – NHRP
periodic downloaded static route, H – NHRP
+ –
replicated route, % – next hop override
replicated route, % – next hop override
Gateway of last resort is not set
1.0.0.0/32 is
subnetted, 1 subnets
subnetted, 1 subnets
C 1.1.1.1 is
directly connected, Loopback0
directly connected, Loopback0
10.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
10.1.1.0/24 is directly connected, FastEthernet2/0
10.1.1.0/24 is directly connected, FastEthernet2/0
L
10.1.1.1/32 is directly connected, FastEthernet2/0
10.1.1.1/32 is directly connected, FastEthernet2/0
12.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
12.12.12.0/24 is directly connected, FastEthernet0/0
12.12.12.0/24 is directly connected, FastEthernet0/0
L
12.12.12.1/32 is directly connected, FastEthernet0/0
12.12.12.1/32 is directly connected, FastEthernet0/0
13.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
13.13.13.0/24 is directly connected, FastEthernet0/1
13.13.13.0/24 is directly connected, FastEthernet0/1
L 13.13.13.1/32
is directly connected, FastEthernet0/1
is directly connected, FastEthernet0/1
20.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 20.1.1.0 [200/0] via 12.12.12.2,
00:37:25 \No change in outgoing traffic
00:37:25 \No change in outgoing traffic
R2:-
Without AS prepend
R2#sh ip bgp summary
BGP router identifier 2.2.2.2, local AS number 1
BGP table version is 5, main routing table version 5
2 network entries using 256 bytes of memory
2 path entries using 104 bytes of memory
2/2 BGP path/bestpath attribute entries using 248 bytes
of memory
of memory
1 BGP AS-PATH entries using 24 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 632 total bytes of memory
BGP activity 11/9 prefixes, 11/9 paths, scan interval 60
secs
secs
Neighbor
V AS MsgRcvd
MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
V AS MsgRcvd
MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
12.12.12.1
4 1 509
517 5 0
0 07:39:45 1
4 1 509
517 5 0
0 07:39:45 1
25.25.25.5
4 2 522
525 5 0
0 07:50:54 1
4 2 522
525 5 0
0 07:50:54 1
R2#sh ip bgp
BGP table version is 5, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid,
> best, i – internal,
> best, i – internal,
r
RIB-failure, S Stale, m multipath, b backup-path, x best-external
RIB-failure, S Stale, m multipath, b backup-path, x best-external
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*>i10.1.1.0/24
12.12.12.1 0 100
0 i
12.12.12.1 0 100
0 i
*> 20.1.1.0/24
25.25.25.5
0 2 i
25.25.25.5
0 2 i
R2#sh ip route
Codes: L – local, C – connected, S – static, R – RIP, M –
mobile, B – BGP
mobile, B – BGP
D – EIGRP,
EX – EIGRP external, O – OSPF, IA – OSPF inter area
EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF
NSSA external type 1, N2 – OSPF NSSA external type 2
NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF
external type 1, E2 – OSPF external type 2
external type 1, E2 – OSPF external type 2
i – IS-IS,
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
ia – IS-IS
inter area, * – candidate default, U – per-user static route
inter area, * – candidate default, U – per-user static route
o – ODR, P –
periodic downloaded static route, H – NHRP
periodic downloaded static route, H – NHRP
+ –
replicated route, % – next hop override
replicated route, % – next hop override
Gateway of last resort is not set
2.0.0.0/32 is
subnetted, 1 subnets
subnetted, 1 subnets
C 2.2.2.2 is
directly connected, Loopback0
directly connected, Loopback0
10.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 10.1.1.0
[200/0] via 12.12.12.1, 07:39:52
[200/0] via 12.12.12.1, 07:39:52
12.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
12.12.12.0/24 is directly connected, FastEthernet0/0
12.12.12.0/24 is directly connected, FastEthernet0/0
L
12.12.12.2/32 is directly connected, FastEthernet0/0
12.12.12.2/32 is directly connected, FastEthernet0/0
20.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 20.1.1.0 [20/0] via 25.25.25.5,
07:50:04
07:50:04
25.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
25.25.25.0/24 is directly connected, FastEthernet1/0
25.25.25.0/24 is directly connected, FastEthernet1/0
L
25.25.25.2/32 is directly connected, FastEthernet1/0
25.25.25.2/32 is directly connected, FastEthernet1/0
R2#
With AS Prepend:-
R2#sh ip route
Codes: L – local, C – connected, S – static, R – RIP, M –
mobile, B – BGP
mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA
– OSPF inter area
– OSPF inter area
N1 – OSPF
NSSA external type 1, N2 – OSPF NSSA external type 2
NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF
external type 1, E2 – OSPF external type 2
external type 1, E2 – OSPF external type 2
i – IS-IS,
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
ia – IS-IS
inter area, * – candidate default, U – per-user static route
inter area, * – candidate default, U – per-user static route
o – ODR, P –
periodic downloaded static route, H – NHRP
periodic downloaded static route, H – NHRP
+ –
replicated route, % – next hop override
replicated route, % – next hop override
Gateway of last resort is not set
2.0.0.0/32 is
subnetted, 1 subnets
subnetted, 1 subnets
C 2.2.2.2 is
directly connected, Loopback0
directly connected, Loopback0
10.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 10.1.1.0
[200/0] via 12.12.12.1, 08:00:35
[200/0] via 12.12.12.1, 08:00:35
12.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
12.12.12.0/24 is directly connected, FastEthernet0/0
12.12.12.0/24 is directly connected, FastEthernet0/0
L
12.12.12.2/32 is directly connected, FastEthernet0/0
12.12.12.2/32 is directly connected, FastEthernet0/0
20.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 20.1.1.0 [20/0] via 25.25.25.5,
08:10:47
08:10:47
25.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
25.25.25.0/24 is directly connected, FastEthernet1/0
25.25.25.0/24 is directly connected, FastEthernet1/0
L
25.25.25.2/32 is directly connected, FastEthernet1/0
25.25.25.2/32 is directly connected, FastEthernet1/0
R3:-
Without AS prepend
R3#sh ip bgp su
BGP router identifier 3.3.3.3, local AS number 1
BGP table version is 3, main routing table version 3
2 network entries using 256 bytes of memory
2 path entries using 104 bytes of memory
2/2 BGP path/bestpath attribute entries using 248 bytes
of memory
of memory
1 BGP AS-PATH entries using 24 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 632 total bytes of memory
BGP activity 5/3 prefixes, 5/3 paths, scan interval 60
secs
secs
Neighbor
V AS MsgRcvd
MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
V AS MsgRcvd
MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
13.13.13.1
4 1 30
33 3 0
0 00:23:58 1
4 1 30
33 3 0
0 00:23:58 1
34.34.34.4
4 2 31
32 3 0
0 00:23:58 1
4 2 31
32 3 0
0 00:23:58 1
R3#sh ip bgp
BGP table version is 3, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid,
> best, i – internal,
> best, i – internal,
r
RIB-failure, S Stale, m multipath, b backup-path, x best-external
RIB-failure, S Stale, m multipath, b backup-path, x best-external
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*>i10.1.1.0/24
13.13.13.1 0 100
0 i
13.13.13.1 0 100
0 i
*>
20.1.1.0/24 34.34.34.4 0 2 i
20.1.1.0/24 34.34.34.4 0 2 i
R3#sh ip route
Codes: L – local, C – connected, S – static, R – RIP, M –
mobile, B – BGP
mobile, B – BGP
D – EIGRP,
EX – EIGRP external, O – OSPF, IA – OSPF inter area
EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF
NSSA external type 1, N2 – OSPF NSSA external type 2
NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF
external type 1, E2 – OSPF external type 2
external type 1, E2 – OSPF external type 2
i – IS-IS,
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
ia – IS-IS
inter area, * – candidate default, U – per-user static route
inter area, * – candidate default, U – per-user static route
o – ODR, P –
periodic downloaded static route, H – NHRP
periodic downloaded static route, H – NHRP
+ –
replicated route, % – next hop override
replicated route, % – next hop override
Gateway of last resort is not set
3.0.0.0/32 is
subnetted, 1 subnets
subnetted, 1 subnets
C 3.3.3.3 is
directly connected, Loopback0
directly connected, Loopback0
10.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 10.1.1.0
[200/0] via 13.13.13.1, 00:23:03
[200/0] via 13.13.13.1, 00:23:03
13.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
13.13.13.0/24 is directly connected, FastEthernet0/1
13.13.13.0/24 is directly connected, FastEthernet0/1
L
13.13.13.3/32 is directly connected, FastEthernet0/1
13.13.13.3/32 is directly connected, FastEthernet0/1
20.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 20.1.1.0 [20/0] via 34.34.34.4,
00:23:03
00:23:03
34.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
34.34.34.0/24 is directly connected, FastEthernet1/0
34.34.34.0/24 is directly connected, FastEthernet1/0
L
34.34.34.3/32 is directly connected, FastEthernet1/0
34.34.34.3/32 is directly connected, FastEthernet1/0
With AS Prepend:-
R3#sh ip route
Codes: L – local, C – connected, S – static, R – RIP, M –
mobile, B – BGP
mobile, B – BGP
D – EIGRP,
EX – EIGRP external, O – OSPF, IA – OSPF inter area
EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF
NSSA external type 1, N2 – OSPF NSSA external type 2
NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF
external type 1, E2 – OSPF external type 2
external type 1, E2 – OSPF external type 2
i – IS-IS,
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
ia – IS-IS inter
area, * – candidate default, U – per-user static route
area, * – candidate default, U – per-user static route
o – ODR, P –
periodic downloaded static route, H – NHRP
periodic downloaded static route, H – NHRP
+ –
replicated route, % – next hop override
replicated route, % – next hop override
Gateway of last resort is not set
3.0.0.0/32 is
subnetted, 1 subnets
subnetted, 1 subnets
C 3.3.3.3 is directly connected, Loopback0
10.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 10.1.1.0
[200/0] via 13.13.13.1, 00:43:14
[200/0] via 13.13.13.1, 00:43:14
13.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
13.13.13.0/24 is directly connected, FastEthernet0/1
13.13.13.0/24 is directly connected, FastEthernet0/1
L
13.13.13.3/32 is directly connected, FastEthernet0/1
13.13.13.3/32 is directly connected, FastEthernet0/1
20.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 20.1.1.0 [20/0] via 34.34.34.4,
00:43:14
00:43:14
34.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
34.34.34.0/24 is directly connected, FastEthernet1/0
34.34.34.0/24 is directly connected, FastEthernet1/0
L
34.34.34.3/32 is directly connected, FastEthernet1/0
34.34.34.3/32 is directly connected, FastEthernet1/0
R4:-
Without AS prepend
R4#sh ip bgp summ
BGP router identifier 4.4.4.4, local AS number 2
BGP table version is 9, main routing table version 9
2 network entries using 256 bytes of memory
2 path entries using 104 bytes of memory
2/2 BGP path/bestpath attribute entries using 248 bytes
of memory
of memory
1 BGP AS-PATH entries using 24 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 632 total bytes of memory
BGP activity 4/2 prefixes, 4/2 paths, scan interval 60
secs
secs
Neighbor
V AS MsgRcvd
MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
V AS MsgRcvd
MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
34.34.34.3
4 1 33
32 9 0
0 00:24:21 1
4 1 33
32 9 0
0 00:24:21 1
46.46.46.6
4 2 609
618 9
0 0 09:12:16 1
4 2 609
618 9
0 0 09:12:16 1
R4#sh ip bgp
BGP table version is 9, local router ID is 4.4.4.4
Status codes: s suppressed, d damped, h history, * valid,
> best, i – internal,
> best, i – internal,
r
RIB-failure, S Stale, m multipath, b backup-path, x best-external
RIB-failure, S Stale, m multipath, b backup-path, x best-external
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*> 10.1.1.0/24
34.34.34.3
0 1 i
34.34.34.3
0 1 i
*>i20.1.1.0/24
46.46.46.6 0 100
0 i
46.46.46.6 0 100
0 i
R4#sh ip rou
Codes: L – local, C – connected, S – static, R – RIP, M –
mobile, B – BGP
mobile, B – BGP
D – EIGRP,
EX – EIGRP external, O – OSPF, IA – OSPF inter area
EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF
NSSA external type 1, N2 – OSPF NSSA external type 2
NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF
external type 1, E2 – OSPF external type 2
external type 1, E2 – OSPF external type 2
i – IS-IS,
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
ia – IS-IS
inter area, * – candidate default, U – per-user static route
inter area, * – candidate default, U – per-user static route
o – ODR, P –
periodic downloaded static route, H – NHRP
periodic downloaded static route, H – NHRP
+ – replicated route, % – next hop override
Gateway of last resort is not set
4.0.0.0/32 is
subnetted, 1 subnets
subnetted, 1 subnets
C 4.4.4.4 is
directly connected, Loopback0
directly connected, Loopback0
10.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 10.1.1.0 [20/0] via 34.34.34.3, 00:18:39
20.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 20.1.1.0
[200/0] via 46.46.46.6, 09:07:54
[200/0] via 46.46.46.6, 09:07:54
34.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
34.34.34.0/24 is directly connected, FastEthernet1/0
34.34.34.0/24 is directly connected, FastEthernet1/0
L
34.34.34.4/32 is directly connected, FastEthernet1/0
34.34.34.4/32 is directly connected, FastEthernet1/0
46.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
46.46.46.0/24 is directly connected, FastEthernet0/1
46.46.46.0/24 is directly connected, FastEthernet0/1
L
46.46.46.4/32 is directly connected, FastEthernet0/1
46.46.46.4/32 is directly connected, FastEthernet0/1
R4#
With AS Prepend:-
R4#sh ip bgp
BGP table version is 10, local router ID is 4.4.4.4
Status codes: s suppressed, d damped, h history, * valid,
> best, i – internal,
> best, i – internal,
r
RIB-failure, S Stale, m multipath, b backup-path, x best-external
RIB-failure, S Stale, m multipath, b backup-path, x best-external
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*>
10.1.1.0/24 34.34.34.3 0 1 1 1 1 1 I
\ Increased the AS path
10.1.1.0/24 34.34.34.3 0 1 1 1 1 1 I
\ Increased the AS path
*>i20.1.1.0/24
46.46.46.6 0 100
0 i
46.46.46.6 0 100
0 i
R4#sh ip route
Codes: L – local, C – connected, S – static, R – RIP, M –
mobile, B – BGP
mobile, B – BGP
D – EIGRP,
EX – EIGRP external, O – OSPF, IA – OSPF inter area
EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF
NSSA external type 1, N2 – OSPF NSSA external type 2
NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF
external type 1, E2 – OSPF external type 2
external type 1, E2 – OSPF external type 2
i – IS-IS,
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
ia – IS-IS
inter area, * – candidate default, U – per-user static route
inter area, * – candidate default, U – per-user static route
o – ODR, P –
periodic downloaded static route, H – NHRP
periodic downloaded static route, H – NHRP
+ –
replicated route, % – next hop override
replicated route, % – next hop override
Gateway of last resort is not set
4.0.0.0/32 is
subnetted, 1 subnets
subnetted, 1 subnets
C 4.4.4.4 is
directly connected, Loopback0
directly connected, Loopback0
10.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 10.1.1.0 [20/0] via 34.34.34.3,
00:10:17
00:10:17
20.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 20.1.1.0
[200/0] via 46.46.46.6, 09:28:03
[200/0] via 46.46.46.6, 09:28:03
34.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C 34.34.34.0/24 is directly connected,
FastEthernet1/0
FastEthernet1/0
L
34.34.34.4/32 is directly connected, FastEthernet1/0
34.34.34.4/32 is directly connected, FastEthernet1/0
46.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
46.46.46.0/24 is directly connected, FastEthernet0/1
46.46.46.0/24 is directly connected, FastEthernet0/1
L
46.46.46.4/32 is directly connected, FastEthernet0/1
46.46.46.4/32 is directly connected, FastEthernet0/1
R5:-
Without AS prepend
R5#sh ip bgp sum
BGP router identifier 5.5.5.5, local AS number 2
BGP table version is 13, main routing table version 13
2 network entries using 256 bytes of memory
2 path entries using 104 bytes of memory
2/2 BGP path/bestpath attribute entries using 248 bytes
of memory
of memory
1 BGP AS-PATH entries using 24 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 632 total bytes of memory
BGP activity 7/5 prefixes, 7/5 paths, scan interval 60
secs
secs
Neighbor
V AS MsgRcvd
MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
V AS MsgRcvd
MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
25.25.25.2
4 1 527
524 13 0
0 07:52:40 1
4 1 527
524 13 0
0 07:52:40 1
56.56.56.6
4 2 614
616 13 0
0 09:12:04 1
4 2 614
616 13 0
0 09:12:04 1
R5#sh ip bgp
BGP table version is 13, local router ID is 5.5.5.5
Status codes: s suppressed, d damped, h history, * valid,
> best, i – internal,
> best, i – internal,
r
RIB-failure, S Stale, m multipath, b backup-path, x best-external
RIB-failure, S Stale, m multipath, b backup-path, x best-external
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*> 10.1.1.0/24
25.25.25.2
0 1 i
25.25.25.2
0 1 i
*>i20.1.1.0/24
56.56.56.6 0 100
0 i
56.56.56.6 0 100
0 i
R5#sh ip route
Codes: L – local, C – connected, S – static, R – RIP, M –
mobile, B – BGP
mobile, B – BGP
D – EIGRP,
EX – EIGRP external, O – OSPF, IA – OSPF inter area
EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF
NSSA external type 1, N2 – OSPF NSSA external type 2
NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF
external type 1, E2 – OSPF external type 2
external type 1, E2 – OSPF external type 2
i – IS-IS,
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
ia – IS-IS
inter area, * – candidate default, U – per-user static route
inter area, * – candidate default, U – per-user static route
o – ODR, P –
periodic downloaded static route, H – NHRP
periodic downloaded static route, H – NHRP
+ –
replicated route, % – next hop override
replicated route, % – next hop override
Gateway of last resort is not set
5.0.0.0/32 is
subnetted, 1 subnets
subnetted, 1 subnets
C 5.5.5.5 is
directly connected, Loopback0
directly connected, Loopback0
10.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 10.1.1.0
[20/0] via 25.25.25.2, 07:41:34
[20/0] via 25.25.25.2, 07:41:34
20.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 20.1.1.0
[200/0] via 56.56.56.6, 09:07:32
[200/0] via 56.56.56.6, 09:07:32
25.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
25.25.25.0/24 is directly connected, FastEthernet1/0
25.25.25.0/24 is directly connected, FastEthernet1/0
L
25.25.25.5/32 is directly connected, FastEthernet1/0
25.25.25.5/32 is directly connected, FastEthernet1/0
56.0.0.0/8 is variably subnetted, 2 subnets,
2 masks
2 masks
C
56.56.56.0/24 is directly connected, FastEthernet0/0
56.56.56.0/24 is directly connected, FastEthernet0/0
L
56.56.56.5/32 is directly connected, FastEthernet0/0
56.56.56.5/32 is directly connected, FastEthernet0/0
R5#
With AS Prepend:-
R5#sh ip bgp
BGP table version is 13, local router ID is 5.5.5.5
Status codes: s suppressed, d damped, h history, * valid,
> best, i – internal,
> best, i – internal,
r
RIB-failure, S Stale, m multipath, b backup-path, x best-external
RIB-failure, S Stale, m multipath, b backup-path, x best-external
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*> 10.1.1.0/24
25.25.25.2
0 1 i
25.25.25.2
0 1 i
*>i20.1.1.0/24
56.56.56.6 0 100
0 i
56.56.56.6 0 100
0 i
R5#sh ip rou
R5#sh ip route
Codes: L – local, C – connected, S – static, R – RIP, M –
mobile, B – BGP
mobile, B – BGP
D – EIGRP,
EX – EIGRP external, O – OSPF, IA – OSPF inter area
EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF
NSSA external type 1, N2 – OSPF NSSA external type 2
NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF
external type 1, E2 – OSPF external type 2
external type 1, E2 – OSPF external type 2
i – IS-IS,
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
ia – IS-IS
inter area, * – candidate default, U – per-user static route
inter area, * – candidate default, U – per-user static route
o – ODR, P –
periodic downloaded static route, H – NHRP
periodic downloaded static route, H – NHRP
+ –
replicated route, % – next hop override
replicated route, % – next hop override
Gateway of last resort is not set
5.0.0.0/32 is
subnetted, 1 subnets
subnetted, 1 subnets
C 5.5.5.5 is
directly connected, Loopback0
directly connected, Loopback0
10.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 10.1.1.0
[20/0] via 25.25.25.2, 08:03:18
[20/0] via 25.25.25.2, 08:03:18
20.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 20.1.1.0 [200/0] via 56.56.56.6,
09:29:16
09:29:16
25.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
25.25.25.0/24 is directly connected, FastEthernet1/0
25.25.25.0/24 is directly connected, FastEthernet1/0
L
25.25.25.5/32 is directly connected, FastEthernet1/0
25.25.25.5/32 is directly connected, FastEthernet1/0
56.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
56.56.56.0/24 is directly connected, FastEthernet0/0
56.56.56.0/24 is directly connected, FastEthernet0/0
L 56.56.56.5/32
is directly connected, FastEthernet0/0
is directly connected, FastEthernet0/0
R6:-
Without AS prepend
R6#sh ip bgp summ
BGP router identifier 6.6.6.6, local AS number 2
BGP table version is 14, main routing table version 14
2 network entries using 256 bytes of memory
3 path entries using 156 bytes of memory
2/2 BGP path/bestpath attribute entries using 248 bytes
of memory
of memory
1 BGP AS-PATH entries using 24 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 684 total bytes of memory
BGP activity 3/1 prefixes, 10/7 paths, scan interval 60
secs
secs
Neighbor
V AS MsgRcvd
MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
V AS MsgRcvd
MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
46.46.46.4
4 2 619
610 14 0
0 09:13:10 1
4 2 619
610 14 0
0 09:13:10 1
56.56.56.5
4 2 617
615 14 0
0 09:13:20 1
4 2 617
615 14 0
0 09:13:20 1
R6#sh ip bgp
BGP table version is 14, local router ID is 6.6.6.6
Status codes: s suppressed, d damped, h history, * valid,
> best, i – internal,
> best, i – internal,
r
RIB-failure, S Stale, m multipath, b backup-path, x best-external
RIB-failure, S Stale, m multipath, b backup-path, x best-external
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*>i10.1.1.0/24
46.46.46.4 0 100
0 1 i
46.46.46.4 0 100
0 1 i
* i
56.56.56.5 0 100
0 1 i
56.56.56.5 0 100
0 1 i
*> 20.1.1.0/24
0.0.0.0 0
32768 i
0.0.0.0 0
32768 i
R6#sh ip route
Codes: L – local, C – connected, S – static, R – RIP, M –
mobile, B – BGP
mobile, B – BGP
D – EIGRP,
EX – EIGRP external, O – OSPF, IA – OSPF inter area
EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF
NSSA external type 1, N2 – OSPF NSSA external type 2
NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF
external type 1, E2 – OSPF external type 2
external type 1, E2 – OSPF external type 2
i – IS-IS,
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
ia – IS-IS
inter area, * – candidate default, U – per-user static route
inter area, * – candidate default, U – per-user static route
o – ODR, P –
periodic downloaded static route, H – NHRP
periodic downloaded static route, H – NHRP
+ –
replicated route, % – next hop override
replicated route, % – next hop override
Gateway of last resort is not set
6.0.0.0/32 is
subnetted, 1 subnets
subnetted, 1 subnets
C 6.6.6.6 is
directly connected, Loopback0
directly connected, Loopback0
10.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 10.1.1.0 [200/0] via 46.46.46.4,
00:14:25
00:14:25
20.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
20.1.1.0/24 is directly connected, FastEthernet2/0
20.1.1.0/24 is directly connected, FastEthernet2/0
L
20.1.1.1/32 is directly connected, FastEthernet2/0
20.1.1.1/32 is directly connected, FastEthernet2/0
46.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
46.46.46.0/24 is directly connected, FastEthernet0/1
46.46.46.0/24 is directly connected, FastEthernet0/1
L
46.46.46.6/32 is directly connected, FastEthernet0/1
46.46.46.6/32 is directly connected, FastEthernet0/1
56.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
56.56.56.0/24 is directly connected, FastEthernet0/0
56.56.56.0/24 is directly connected, FastEthernet0/0
L
56.56.56.6/32 is directly connected, FastEthernet0/0
56.56.56.6/32 is directly connected, FastEthernet0/0
R6#
With AS Prepend:-
R6#sh ip bgp
BGP table version is 15, local router ID is 6.6.6.6
Status codes: s suppressed, d damped, h history, * valid,
> best, i – internal,
> best, i – internal,
r
RIB-failure, S Stale, m multipath, b backup-path, x best-external
RIB-failure, S Stale, m multipath, b backup-path, x best-external
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*
i10.1.1.0/24 46.46.46.4 0 100
0 1 1 1 1 1 I \Modified AS path received on R6
from R4
i10.1.1.0/24 46.46.46.4 0 100
0 1 1 1 1 1 I \Modified AS path received on R6
from R4
*>i 56.56.56.5 0 100
0 1 I \Preferred path
0 1 I \Preferred path
*> 20.1.1.0/24
0.0.0.0 0 32768 i
0.0.0.0 0 32768 i
R6#sh ip route
Codes: L – local, C – connected, S – static, R – RIP, M –
mobile, B – BGP
mobile, B – BGP
D – EIGRP,
EX – EIGRP external, O – OSPF, IA – OSPF inter area
EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF
NSSA external type 2
NSSA external type 2
E1 – OSPF
external type 1, E2 – OSPF external type 2
external type 1, E2 – OSPF external type 2
i – IS-IS,
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2
ia – IS-IS
inter area, * – candidate default, U – per-user static route
inter area, * – candidate default, U – per-user static route
o – ODR, P –
periodic downloaded static route, H – NHRP
periodic downloaded static route, H – NHRP
+ –
replicated route, % – next hop override
replicated route, % – next hop override
Gateway of last resort is not set
6.0.0.0/32 is
subnetted, 1 subnets
subnetted, 1 subnets
C 6.6.6.6 is
directly connected, Loopback0
directly connected, Loopback0
10.0.0.0/24
is subnetted, 1 subnets
is subnetted, 1 subnets
B 10.1.1.0 [200/0] via 56.56.56.5,
00:12:44
00:12:44
20.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
20.1.1.0/24 is directly connected, FastEthernet2/0
20.1.1.0/24 is directly connected, FastEthernet2/0
L
20.1.1.1/32 is directly connected, FastEthernet2/0
20.1.1.1/32 is directly connected, FastEthernet2/0
46.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
46.46.46.0/24 is directly connected, FastEthernet0/1
46.46.46.0/24 is directly connected, FastEthernet0/1
L
46.46.46.6/32 is directly connected, FastEthernet0/1
46.46.46.6/32 is directly connected, FastEthernet0/1
56.0.0.0/8 is
variably subnetted, 2 subnets, 2 masks
variably subnetted, 2 subnets, 2 masks
C
56.56.56.0/24 is directly connected, FastEthernet0/0
56.56.56.0/24 is directly connected, FastEthernet0/0
L
56.56.56.6/32 is directly connected, FastEthernet0/0
56.56.56.6/32 is directly connected, FastEthernet0/0
R6#
PC1:-
Without AS prepend
PC1> trace 20.1.1.10
trace to 20.1.1.10, 8 hops max, press Ctrl+C to stop
1 10.1.1.1
10.000 ms 10.000 ms 20.000 ms
10.000 ms 10.000 ms 20.000 ms
2 12.12.12.2
30.000 ms 30.000 ms 30.000 ms \R2
30.000 ms 30.000 ms 30.000 ms \R2
3 25.25.25.5
50.000 ms 50.000 ms 50.000 ms
\R5
50.000 ms 50.000 ms 50.000 ms
\R5
4 56.56.56.6
80.000 ms 60.000 ms 50.000 ms
\R6
80.000 ms 60.000 ms 50.000 ms
\R6
5 *20.1.1.10
80.000 ms (ICMP type:3, code:3, Destination port unreachable)
80.000 ms (ICMP type:3, code:3, Destination port unreachable)
With AS Prepend:-
PC1> trace 20.1.1.10
–<< No change
–<< No change
trace to 20.1.1.10, 8 hops max, press Ctrl+C to stop
1 10.1.1.1
10.000 ms 10.000 ms 10.000 ms
10.000 ms 10.000 ms 10.000 ms
2 12.12.12.2
50.000 ms 30.000 ms 30.000 ms
\R2
50.000 ms 30.000 ms 30.000 ms
\R2
3 25.25.25.5
50.000 ms 50.000 ms 50.000 ms
\R5
50.000 ms 50.000 ms 50.000 ms
\R5
4 56.56.56.6
60.000 ms 60.000 ms 60.000 ms
\R6
60.000 ms 60.000 ms 60.000 ms
\R6
5 20.1.1.10 70.000 ms (ICMP type:3, code:3, Destination
port unreachable)
port unreachable)
PC2:-
Without AS prepend
C2> trace 10.1.1.10
trace to 10.1.1.10, 8 hops max, press Ctrl+C to stop
1 20.1.1.1
10.000 ms 10.000 ms 10.000 ms
10.000 ms 10.000 ms 10.000 ms
2 46.46.46.4
30.000 ms 30.000 ms 30.000 ms \R4
30.000 ms 30.000 ms 30.000 ms \R4
3
34.34.34.3 50.000 ms 40.000 ms
50.000 ms \R3
34.34.34.3 50.000 ms 40.000 ms
50.000 ms \R3
4
13.13.13.1 50.000 ms 70.000 ms
70.000 ms \R1
13.13.13.1 50.000 ms 70.000 ms
70.000 ms \R1
5 *10.1.1.10
70.000 ms (ICMP type:3, code:3, Destination port unreachable)
70.000 ms (ICMP type:3, code:3, Destination port unreachable)
With AS Prepend:-
PC2> trace 10.1.1.10
trace to 10.1.1.10, 8 hops max, press Ctrl+C to stop
1 20.1.1.1
10.000 ms 10.000 ms 10.000 ms
10.000 ms 10.000 ms 10.000 ms
2 56.56.56.5
20.000 ms 30.000 ms 30.000 ms \R5
20.000 ms 30.000 ms 30.000 ms \R5
3
25.25.25.2 30.000 ms 40.000 ms
30.000 ms \R2
25.25.25.2 30.000 ms 40.000 ms
30.000 ms \R2
4
12.12.12.1 70.000 ms 70.000 ms
60.000 ms \R1
12.12.12.1 70.000 ms 70.000 ms
60.000 ms \R1
5 *10.1.1.10
80.000 ms (ICMP type:3, code:3, Destination port unreachable)
80.000 ms (ICMP type:3, code:3, Destination port unreachable)