David Sudjiman

Using topology shown in Figure, I configured the network as such

R2 configuration

int s0.1
  ip addr 20.20.20.2 255.255.255.248
  e f
  frame-relay map ip 20.20.20.1 111 b
  frame-relay map clns 111 b
  ip router isis
!
router isis
  net 49.0002.0000.0000.000b.00
  is-type level2-only

R1 conf

int s0
e f
!
int s0.1 m
  ip addr 20.20.20.1 255.255.255.248
  frame-relay map ip 20.20.20.2 222 b
  frame-relay map clns 222 b
  ip router isis
  isis circuit-type level-2-only
|
int s0.2 p
  ip addr 30.30.30.1 255.255.255.252
  frame-relay interface-dlci 444
  ip router isis
  isis circuit-type level-1
!
router isis
  net 49.0001.0000.0000.000a.00

R4 conf

int s0
  ip addr 30.30.30.2 255.255.255.252
  e f
  frame-relay interface-dlci 111
  ip router isis
!
router isis
  net 49.0001.0000.0000.000b.00
 is-type level-1

R2 sh ip route

      20.0.0.0/29 is subnetted, 1 subnets
C       20.20.20.0 is directly connected, Serial0
      30.0.0.0/30 is subnetted, 1 subnets
i L2    30.30.30.0 [115/20] via 20.20.20.1, Serial0

Ping results from R2

ping 20.20.20.1 OK
ping 30.30.30.1 OK
ping 30.30.30.2 FAIL

R1 sh ip route

     20.0.0.0/29 is subnetted, 1 subnets
C       20.20.20.0 is directly connected, Serial0.1
     30.0.0.0/30 is subnetted, 1 subnets
C       30.30.30.0 is directly connected, Serial0.2

Ping results from R1

ping 20.20.20.2 OK
ping 30.30.30.2 OK

R4 sh ip route

     30.0.0.0/30 is subnetted, 1 subnets
C       30.30.30.0 is directly connected, Serial0

Ping results from R4

ping 30.30.30.1 OK
ping 20.20.20.1 FAIL
ping 20.20.20.2 FAIL

From the configuration above, the problem was R4 did not have routing information to network 20.20.20.0/29. Therefore, pinging from R4 to network 20.20.20.0/29 would fail. However, R2 had the routing information for network 30.30.30.0/30 shown above.

Using debug isis update-packets on R4 and restarting the interface showed this

00:15:37: ISIS-Upd: Building L1 LSP
00:15:37: ISIS-Upd: TLV code mismatch (2, 132)
00:15:37: ISIS-Upd: Full SPF required
00:15:38: ISIS-Upd: Building L2 LSP
00:15:38: ISIS-Upd: TLV code mismatch (2, 132)
00:15:38: ISIS-Upd: Full SPF required
00:15:58: ISIS-Upd: Building L1 LSP
00:15:58: ISIS-Upd: TLV contents different, code 2
00:15:58: ISIS-Upd: Full SPF required
00:15:59: ISIS-Upd: Building L1 pseudonode LSP for Serial0
00:15:59: ISIS-Upd: New LSP
00:15:59: ISIS-Upd: Full SPF required

Searching on www.cisco.com for TLV code mismatch showed this

TLV code mismatch

http://www.cisco.com/en/US/products/sw/iosswrel/ps1826/products_command_reference_chapter09186a00800e0438.html

TLVCODE–TLV code mismatch, indicating that different TLVs are included in the newest version of an LSP.

Not much of information, I also tried the TLV contents different but it showed stuffs for IPv6 and MPLS

Next thing, I tried debug isis adj-packets and found something very interesting.

00:27:24: ISIS-Adj: Rec serial IIH from DLCI 111 (Serial0), cir type L1, cir id 00, length 1499
00:27:24: ISIS-Adj: Point-to-point IIH received on multi-point interface: ignored IIH
00:27:24: ISIS-Adj: Encapsulation failed for L1 LAN IIH on Serial0

Did you see that? Point-to-point IIH received on multi-point interface: ignored IIH and Encapsulation failed for L1 LAN IIH on Serial0 showed that you are using different encapsulation as multipoint interface received point-to-point IIH. Remember that command interface s0 with encapsulation frame-relay on R4 will automatically create multipoint frame-relay while the other adjacent router R1 was using frame-relay point-to-point.

Therefore, changing the R4 configuration to use point-to-point solved the problem.

int s0
e f
int s0.1 point-to-point
  ip addr 30.30.30.2 255.255.255.252
  frame-relay interface-dlci 111
  ip router isis
!
router isis
  net 49.0001.0000.0000.000b.00
 is-type level-1

R4 sh ip route

Gateway of last resort is 30.30.30.1 to network 0.0.0.0

     30.0.0.0/30 is subnetted, 1 subnets
C       30.30.30.0 is directly connected, Serial0.1
i*L1 0.0.0.0/0 [115/10] via 30.30.30.1, Serial0.1

debug isis adj-packets

00:38:45: ISIS-Adj: Sending serial IIH on Serial0.1, length 1499
00:38:46: ISIS-Adj: Rec serial IIH from DLCI 111 (Serial0.1), cir type L1, cir id 00, length 1499
00:38:46: ISIS-Adj: rcvd state UP, old state UP, new state UP
00:38:46: ISIS-Adj: Action = ACCEPT

Ping results from R4

R4#ping 20.20.20.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 20.20.20.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 132/133/140 ms