I have a following physical topology:
C1841[Fa0/0] <-> [Fa1/0/1]
ME-C3750-24TE. Both in
C1841 and
ME-C3750-24TE there is a tunnel configured:
C1841#sh run int Tu0
Building configuration...
Current configuration : 150 bytes
!
interface Tunnel0
ip unnumbered FastEthernet0/1
keepalive 5 3
tunnel source FastEthernet0/0
tunnel destination 10.10.10.1
tunnel checksum
end
C1841#
ME-C3750-24TE#sh run int Tu0
Building configuration...
Current configuration : 134 bytes
!
interface Tunnel0
ip unnumbered Vlan100
keepalive 5 3
tunnel source Vlan200
tunnel destination 10.10.10.2
tunnel checksum
end
ME-C3750-24TE#
The problem is, that while line protocol of Tu0 in
ME-C3750-24TE is up, it is down in
C1841:
ME-C3750-24TE#sh int Tu0
Tunnel0 is up, line protocol is up
Hardware is Tunnel
Interface is unnumbered. Using address of Vlan100 (192.168.2.2)
MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation TUNNEL, loopback not set
Keepalive set (5 sec), retries 3
Tunnel source 10.10.10.1 (Vlan200), destination 10.10.10.2
Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled
Tunnel TTL 255
Checksumming of packets enabled
Last input 00:00:02, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 10
Queueing strategy: fifo
Output queue: 0/0 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
1689 packets input, 94576 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
1730 packets output, 96880 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
ME-C3750-24TE#
C1841#sh int Tu0
Tunnel0 is up, line protocol is down
Hardware is Tunnel
Interface is unnumbered. Using address of FastEthernet0/1 (192.168.1.2)
MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation TUNNEL, loopback not set
Keepalive set (5 sec), retries 3
Tunnel source 10.10.10.2 (FastEthernet0/0), destination 10.10.10.1
Tunnel protocol/transport GRE/IP
Key disabled, sequencing disabled
Checksumming of packets enabled
Tunnel TTL 255
Fast tunneling enabled
Tunnel transmit bandwidth 8000 (kbps)
Tunnel receive bandwidth 8000 (kbps)
Last input 00:00:02, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 8
Queueing strategy: fifo
Output queue: 0/0 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
1691 packets input, 94696 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
1700 packets output, 95192 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
C1841#
Tunnel destinations are reachable:
C1841#sh ip int bri
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 10.10.10.2 YES manual up up
FastEthernet0/1 192.168.1.2 YES manual up up
Tunnel0 192.168.1.2 YES TFTP up down
C1841#ping 10.10.10.1 source 10.10.10.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.10.10.1, timeout is 2 seconds:
Packet sent with a source address of 10.10.10.2
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
C1841#
ME-C3750-24TE#sh ip int bri | i Vlan|Tu
Vlan1 unassigned YES unset administratively down down
Vlan100 192.168.2.2 YES manual up up
Vlan200 10.10.10.1 YES manual up up
Tunnel0 192.168.2.2 YES unset up up
ME-C3750-24TE#ping 10.10.10.2 source 10.10.10.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.10.10.2, timeout is 2 seconds:
Packet sent with a source address of 10.10.10.1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/8 ms
ME-C3750-24TE#
Any ideas why line protocol of Tu0 in
C1841 router is down?
I have a following physical topology:
C1841[Fa0/0] <-> [Fa1/0/1]
ME-C3750-24TE. Both in
C1841 and
ME-C3750-24TE there is a tunnel configured:
C1841#sh run int Tu0
Building configuration...
Current configuration : 150 bytes
!
interface Tunnel0
ip unnumbered FastEthernet0/1
keepalive 5 3
tunnel source FastEthernet0/0
tunnel destination 10.10.10.1
tunnel checksum
end
C1841#
ME-C3750-24TE#sh run int Tu0
Building configuration...
Current configuration : 134 bytes
!
interface Tunnel0
ip unnumbered Vlan100
keepalive 5 3
tunnel source Vlan200
tunnel destination 10.10.10.2
tunnel checksum
end
ME-C3750-24TE#
The problem is, that while line protocol of Tu0 in
ME-C3750-24TE is up, it is down in
C1841:
ME-C3750-24TE#sh int Tu0
Tunnel0 is up, line protocol is up
Hardware is Tunnel
Interface is unnumbered. Using address of Vlan100 (192.168.2.2)
MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation TUNNEL, loopback not set
Keepalive set (5 sec), retries 3
Tunnel source 10.10.10.1 (Vlan200), destination 10.10.10.2
Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled
Tunnel TTL 255
Checksumming of packets enabled
Last input 00:00:02, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 10
Queueing strategy: fifo
Output queue: 0/0 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
1689 packets input, 94576 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
1730 packets output, 96880 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
ME-C3750-24TE#
C1841#sh int Tu0
Tunnel0 is up, line protocol is down
Hardware is Tunnel
Interface is unnumbered. Using address of FastEthernet0/1 (192.168.1.2)
MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation TUNNEL, loopback not set
Keepalive set (5 sec), retries 3
Tunnel source 10.10.10.2 (FastEthernet0/0), destination 10.10.10.1
Tunnel protocol/transport GRE/IP
Key disabled, sequencing disabled
Checksumming of packets enabled
Tunnel TTL 255
Fast tunneling enabled
Tunnel transmit bandwidth 8000 (kbps)
Tunnel receive bandwidth 8000 (kbps)
Last input 00:00:02, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 8
Queueing strategy: fifo
Output queue: 0/0 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
1691 packets input, 94696 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
1700 packets output, 95192 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
C1841#
Tunnel destinations are reachable:
C1841#sh ip int bri
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 10.10.10.2 YES manual up up
FastEthernet0/1 192.168.1.2 YES manual up up
Tunnel0 192.168.1.2 YES TFTP up down
C1841#ping 10.10.10.1 source 10.10.10.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.10.10.1, timeout is 2 seconds:
Packet sent with a source address of 10.10.10.2
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
C1841#
ME-C3750-24TE#sh ip int bri | i Vlan|Tu
Vlan1 unassigned YES unset administratively down down
Vlan100 192.168.2.2 YES manual up up
Vlan200 10.10.10.1 YES manual up up
Tunnel0 192.168.2.2 YES unset up up
ME-C3750-24TE#ping 10.10.10.2 source 10.10.10.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.10.10.2, timeout is 2 seconds:
Packet sent with a source address of 10.10.10.1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/8 ms
ME-C3750-24TE#
Any ideas why line protocol of Tu0 in
C1841 router is down?
//I disabled keepalives under
ME-C3750-24TE interface Tu0 configuration in order to avoid confusion and ran GRE debugging in
C1841 and
ME-C3750-24TE:
C1841#show debugging
General-purpose tunnel:
Tunnel Interface debugging is on
Tunnel keepalive debugging is on
C1841#
ME-C3750-24TE#show debugging
General-purpose tunnel:
Tunnel Interface debugging is on
Tunnel keepalive debugging is on
ME-C3750-24TE#
Keepalives under
C1841 Tu0 are enabled. Results are following:
Cisco C1841:
C1841#
*Jul 27 11:21:58.574: Tunnel0: sending keepalive, 10.10.10.1->10.10.10.2 (len=28 ttl=255), counter=5
*Jul 27 11:21:58.574: Tunnel0: GRE/IP encapsulated 10.10.10.2->10.10.10.1 (linktype=7, len=56)
C1841#
*Jul 27 11:22:03.574: Tunnel0: sending keepalive, 10.10.10.1->10.10.10.2 (len=28 ttl=255), counter=6
*Jul 27 11:22:03.574: Tunnel0: GRE/IP encapsulated 10.10.10.2->10.10.10.1 (linktype=7, len=56)
C1841#
*Jul 27 11:22:08.574: Tunnel0: sending keepalive, 10.10.10.1->10.10.10.2 (len=28 ttl=255), counter=7
*Jul 27 11:22:08.574: Tunnel0: GRE/IP encapsulated 10.10.10.2->10.10.10.1 (linktype=7, len=56)
C1841#
*Jul 27 11:22:13.574: Tunnel0: sending keepalive, 10.10.10.1->10.10.10.2 (len=28 ttl=255), counter=8
*Jul 27 11:22:13.574: Tunnel0: GRE/IP encapsulated 10.10.10.2->10.10.10.1 (linktype=7, len=56)
C1841#
Cisco
ME-C3750-24TE:
ME-C3750-24TE#
04:17:41: Tunnel0: GRE/IP (PS) to decaps 10.10.10.2->10.10.10.1 (tbl=0,"default" len=56 ttl=255)
04:17:41: Tunnel0: GRE decapsulated IP packet (linktype=7, len=2[IMG]https://us.v-cdn.net/6030959/uploads/images/smilies/icon_cool.gif[/IMG]
ME-C3750-24TE#
04:17:46: Tunnel0: GRE/IP (PS) to decaps 10.10.10.2->10.10.10.1 (tbl=0,"default" len=56 ttl=255)
04:17:46: Tunnel0: GRE decapsulated IP packet (linktype=7, len=2[IMG]https://us.v-cdn.net/6030959/uploads/images/smilies/icon_cool.gif[/IMG]
ME-C3750-24TE#
04:17:51: Tunnel0: GRE/IP (PS) to decaps 10.10.10.2->10.10.10.1 (tbl=0,"default" len=56 ttl=255)
04:17:51: Tunnel0: GRE decapsulated IP packet (linktype=7, len=2[IMG]https://us.v-cdn.net/6030959/uploads/images/smilies/icon_cool.gif[/IMG]
ME-C3750-24TE#
04:17:56: Tunnel0: GRE/IP (PS) to decaps 10.10.10.2->10.10.10.1 (tbl=0,"default" len=56 ttl=255)
04:17:56: Tunnel0: GRE decapsulated IP packet (linktype=7, len=2[IMG]https://us.v-cdn.net/6030959/uploads/images/smilies/icon_cool.gif[/IMG]
ME-C3750-24TE#
Looks like the
ME-C3750-24TE does not reply to GRE keepalives?
