From: iosluver@gmail.com
Date: Wed Nov 28 2007 - 12:21:56 ART
Hi GS,
I wanted to get some opinions on a task I came across which behaved in a manner I didn't expect. Here are the details:
R3 -----Frame-Relay------- R4 -----Frame-Relay-------R5
Instructions:-
**********************
Use R4 as Hub.
Use only physical interfaces on R4 & R3
Use a sub-interface on R5
Do not use FRAME-RELAY MAP command on R5
Do not use any DYNAMIC layer 3 to 2 mappings on these connections
DO not send redundant broadcast traffic to the spokes
Configure OSPF Area 0 on the segment between R3,R4 & R5
Do not use IP OSPF NETWORK command.
Here is what I did:-
R3
****
interface Serial1/1
encapsulation frame-relay
frame-relay interface-dlci 314 ppp Virtual-Template1
interface Virtual-Template1
ip address 142.1.0.3 255.255.255.0
ip ospf hello-interval 3
!
router ospf 1
router-id 150.1.3.3
log-adjacency-changes
network 142.1.0.3 0.0.0.0 area 0
network 150.1.3.3 0.0.0.0 area 0
!
R4
***
interface Serial1/0
no ip address
encapsulation frame-relay
frame-relay interface-dlci 405 ppp Virtual-Template1
frame-relay interface-dlci 413 ppp Virtual-Template1
interface Virtual-Template1
ip address 142.1.0.4 255.255.255.0
ip ospf network point-to-multipoint
ip ospf hello-interval 3
!
router ospf 1
router-id 150.1.4.4
log-adjacency-changes
network 142.1.0.4 0.0.0.0 area 0
network 150.1.4.4 0.0.0.0 area 0
R5
***
interface Serial1/0.504 multipoint
frame-relay interface-dlci 504 ppp Virtual-Template1
!
interface Virtual-Template1
ip address 142.1.0.5 255.255.255.0
ip ospf hello-interval 3
!
router ospf 1
router-id 150.1.5.5
log-adjacency-changes
network 142.1.0.5 0.0.0.0 area 0
network 150.1.5.5 0.0.0.0 area 0
The solution did not change the network type on R4 as its a violation of the one of instructions. Without that command, R4 does not ANY certain routes learnt from R3 to its routing table. It does however forward the LSAs to R3 which installs them as valid routes which can't be reached via R4. For obvious reasons I reduced the hello time. Some output(connected routes) were removed for brevity. All suggestions are welcome. I can send more debugs, log messages if required. Let me know what you think.
R3 Routing Table
****************
O 150.1.5.5/32 [110/3] via 142.1.0.4, 00:02:09, Virtual-Access2
O 150.1.4.4/32 [110/2] via 142.1.0.4, 00:02:11, Virtual-Access2
R4 Routing Table
****************
Rack1R4#sh ip route
C 150.1.4.0/24 is directly connected, Loopback0
O 150.1.5.5/32 [110/2] via 142.1.0.5, 00:02:41, Virtual-Access3
R5 Routing Table
*****************
150.1.0.0/16 is variably subnetted, 3 subnets, 2 masks
O 150.1.4.4/32 [110/2] via 142.1.0.4, 00:05:34, Virtual-Access2
O IA 150.1.3.3/32 [110/3] via 142.1.0.4, 00:05:34, Virtual-Access2
OSPF DATABASE - R4 - Without point-to-multipoint
************************************************
Adv Router is not-reachable
LS age: 491
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 150.1.3.3
Advertising Router: 150.1.3.3
LS Seq Number: 80000009
Checksum: 0x63B9
Length: 48
Area Border Router
Number of Links: 2
OSPF DATABASE - R4 - with point-to-multipoint
*********************************************
Routing Bit Set on this LSA
LS age: 264
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 150.1.3.3
Advertising Router: 150.1.3.3
LS Seq Number: 80000009
Checksum: 0x63B9
Length: 48
Area Border Router
Number of Links: 2
Many Thanks in advance
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