From: Michael Zuo (mzuo@ixiacom.com)
Date: Sat Jan 27 2007 - 23:36:30 ART
So far I narrowed the problem down to the two switches not being able to
ping each other over the trunk (see debug output below, post at 8:38pm).
The ARPs can go one way but not the other and apparently this is no a
UDLD issue. I am more or less lost ...
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Michael Zuo
> Sent: Saturday, January 27, 2007 8:38 PM
> To: Muizebelt Danny; ccielab groupstudy; Sergey Golovanov
> Subject: RE: ICMP showing encapsulation failed
>
> I have narrowed problem down to two adjacent switches can not ping
each
> other over the trunk link and collected debug info as follows (note
that
> the ARP debug shows that CAT2 responded to ARP but CAT1 never received
> the response. Also the trunk link between the two is f0/14 on both
> sides, I verified the physical connection by shut/no shut on the
> interface and watch the same interface go up and down on the other
> switch):
>
>
> CAT1(config-if)#do sh vlan
>
> VLAN Name Status Ports
> ---- -------------------------------- ---------
> -------------------------------
> 1 default active Fa0/1, Fa0/3, Fa0/5,
> Fa0/7
> Fa0/9, Fa0/10, Fa0/11,
> Fa0/12
> Fa0/15, Fa0/16,
Fa0/17,
> Fa0/18
> Fa0/19, Fa0/20,
Fa0/21,
> Fa0/24
> Gi0/1, Gi0/2
> 10 NET-10 active Fa0/2
> 20 NET-20 active Fa0/6
> 30 NET-30 active Fa0/4
> 40 NET-40 active
> 101 VLAN0101 active
> 102 VLAN0102 active
> 1002 fddi-default act/unsup
> 1003 token-ring-default act/unsup
> 1004 fddinet-default act/unsup
> 1005 trnet-default act/unsup
> 3000 VLAN3000 active
>
> VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode
Trans1
> Trans2
> ---- ----- ---------- ----- ------ ------ -------- ---- --------
------
> ------
> 1 enet 100001 1500 - - - - - 0
> 0
>
> CAT1(config-if)#do sh run int vlan 30
> Building configuration...
>
> Current configuration : 63 bytes
> !
> interface Vlan30
> ip address 172.16.34.10 255.255.255.0
> end
>
> CAT1(config-if)#
> CAT1(config-if)#
> CAT1(config-if)#
> CAT1(config-if)#do sh int trun
>
> Port Mode Encapsulation Status Native vlan
> Fa0/8 on 802.1q trunking 1
> Fa0/13 on isl trunking 1
> Fa0/14 on 802.1q trunking 1
> Fa0/22 desirable 802.1q trunking 1
> Fa0/23 desirable 802.1q trunking 1
>
> Port Vlans allowed on trunk
> Fa0/8 1-4094
> Fa0/13 10
> Fa0/14 1,20,30,40
> Fa0/22 1-4094
> Fa0/23 1-4094
>
> Port Vlans allowed and active in management domain
> Fa0/8 1,10,20,30,40,101-102,3000
> Fa0/13 10
> Fa0/14 1,20,30,40
> Fa0/22 1,10,20,30,40,101-102,3000
> Fa0/23 1,10,20,30,40,101-102,3000
>
> Port Vlans in spanning tree forwarding state and not pruned
>
> Port Vlans in spanning tree forwarding state and not pruned
> Fa0/8 1,10,20,30,40,101-102,3000
> Fa0/13 10
> Fa0/14 1,20,30,40
> Fa0/22 1,10,20,30,40,101-102,3000
> Fa0/23 1,10,20,30,40,101-102,3000
> CAT1(config-if)#do sh span vlan 30
>
> VLAN0030
> Spanning tree enabled protocol ieee
> Root ID Priority 32798
> Address 0011.20a9.9280
> This bridge is the root
> Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
>
> Bridge ID Priority 32798 (priority 32768 sys-id-ext 30)
> Address 0011.20a9.9280
> Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
> Aging Time 300
>
> Interface Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- --------
> --------------------------------
> Fa0/4 Desg FWD 19 128.4 P2p
> Fa0/8 Desg FWD 19 128.8 P2p
> Fa0/14 Desg FWD 19 128.14 P2p
> Fa0/22 Desg FWD 19 128.22 P2p
> Fa0/23 Desg FWD 19 128.23 P2p
>
> CAT1(config-if)#do deb arp
> ARP packet debugging is on
> CAT1(config-if)#do ping 172.16.34.11
>
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 172.16.34.11, timeout is 2 seconds:
>
> 00:28:03: IP ARP: creating incomplete entry for IP address:
172.16.34.11
> interfa
> ce Vlan30
> 00:28:03: IP ARP: sent req src 172.16.34.10 0011.20a9.9280,
> dst 172.16.34.11 0000.0000.0000 Vlan30.
> 00:28:05: IP ARP: sent req src 172.16.34.10 0011.20a9.9280,
> dst 172.16.34.11 0000.0000.0000 Vlan30.
> 00:28:07: IP ARP: sent req src 172.16.34.10 0011.20a9.9280,
> dst 172.16.34.11 0000.0000.0000 Vlan30.
> 00:28:09: IP ARP: sent req src 172.16.34.10 0011.20a9.9280,
> dst 172.16.34.11 0000.0000.0000 Vlan30.
> 00:28:11: IP ARP: sent req src 172.16.34.10 0011.20a9.9280,
> dst 172.16.34.11 0000.0000.0000 Vlan30.
> Success rate is 0 percent (0/5)
> CAT1(config-if)#
>
>
>
> CAT2(config-if)#do sh vlan
>
> VLAN Name Status Ports
> ---- -------------------------------- ---------
> -------------------------------
> 1 default active Fa0/2, Fa0/4, Fa0/6,
> Fa0/7
> Fa0/8, Fa0/9, Fa0/10,
> Fa0/11
> Fa0/12, Fa0/15,
Fa0/16,
> Fa0/17
> Fa0/18, Fa0/19,
Fa0/20,
> Fa0/21
> Fa0/24, Gi0/1, Gi0/2
> 10 NET-10 active
> 20 NET-20 active Fa0/3
> 30 NET-30 active Fa0/5
> 40 NET-40 active Fa0/1
> 101 VLAN0101 active
> 102 VLAN0102 active
> 1002 fddi-default act/unsup
> 1003 token-ring-default act/unsup
> 1004 fddinet-default act/unsup
> 1005 trnet-default act/unsup
>
> VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode
Trans1
> Trans2
> ---- ----- ---------- ----- ------ ------ -------- ---- --------
------
> ------
> 1 enet 100001 1500 - - - - - 0
> 0
> 10 enet 100010 1500 - - - - - 0
> 0
>
> CAT2(config-if)#do sh run int vlan 30
> Building configuration...
>
> Current configuration : 63 bytes
> !
> interface Vlan30
> ip address 172.16.34.11 255.255.255.0
> end
>
> CAT2(config-if)#do sh int trun
>
> Port Mode Encapsulation Status Native vlan
> Fa0/13 on isl trunking 1
> Fa0/14 on 802.1q trunking 1
> Fa0/22 desirable 802.1q trunking 1
> Fa0/23 desirable 802.1q trunking 1
>
> Port Vlans allowed on trunk
> Fa0/13 10
> Fa0/14 1,20,30,40
> Fa0/22 1-4094
> Fa0/23 1-4094
>
> Port Vlans allowed and active in management domain
> Fa0/13 10
> Fa0/14 1,20,30,40
> Fa0/22 1,10,20,30,40,101-102
> Fa0/23 1,10,20,30,40,101-102
>
> Port Vlans in spanning tree forwarding state and not pruned
> Fa0/13 10
> Fa0/14 1
> Fa0/22 1
>
> Port Vlans in spanning tree forwarding state and not pruned
> Fa0/23 1
> CAT2(config-if)#do sh span vlan 30
>
> VLAN0030
> Spanning tree enabled protocol ieee
> Root ID Priority 32798
> Address 0011.20a9.9280
> Cost 19
> Port 14 (FastEthernet0/14)
> Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
>
> Bridge ID Priority 32798 (priority 32768 sys-id-ext 30)
> Address 0011.5c63.0e00
> Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
> Aging Time 300
>
> Interface Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- --------
> --------------------------------
> Fa0/5 Desg FWD 19 128.5 P2p
> Fa0/14 Root FWD 19 128.14 P2p
> Fa0/22 Desg FWD 19 128.22 P2p
> Fa0/23 Desg FWD 19 128.23 P2p
>
> CAT2(config-if)#do deb arp
> ARP packet debugging is on
> CAT2(config-if)#
> 00:28:09: IP ARP: rcvd req src 172.16.34.10 0011.20a9.9280, dst
> 172.16.34.11 Vla
> n30
> 00:28:09: IP ARP: sent rep src 172.16.34.11 0011.5c63.0e00,
> dst 172.16.34.10 0011.20a9.9280 Vlan30
> CAT2(config-if)#
> 00:28:11: IP ARP: rcvd req src 172.16.34.10 0011.20a9.9280, dst
> 172.16.34.11 Vla
> n30
> 00:28:11: IP ARP: sent rep src 172.16.34.11 0011.5c63.0e00,
> dst 172.16.34.10 0011.20a9.9280 Vlan30
> CAT2(config-if)#
> 00:28:13: IP ARP: rcvd req src 172.16.34.10 0011.20a9.9280, dst
> 172.16.34.11 Vla
> n30
> 00:28:13: IP ARP: sent rep src 172.16.34.11 0011.5c63.0e00,
> dst 172.16.34.10 0011.20a9.9280 Vlan30
> CAT2(config-if)#
> 00:28:15: IP ARP: rcvd req src 172.16.34.10 0011.20a9.9280, dst
> 172.16.34.11 Vla
> n30
> 00:28:15: IP ARP: sent rep src 172.16.34.11 0011.5c63.0e00,
> dst 172.16.34.10 0011.20a9.9280 Vlan30
> CAT2(config-if)#
> 00:28:17: IP ARP: rcvd req src 172.16.34.10 0011.20a9.9280, dst
> 172.16.34.11 Vla
> n30
> 00:28:17: IP ARP: sent rep src 172.16.34.11 0011.5c63.0e00,
> dst 172.16.34.10 0011.20a9.9280 Vlan30
> CAT2(config-if)#
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Michael Zuo
> Sent: Saturday, January 27, 2007 5:12 PM
> To: Muizebelt Danny; ccielab groupstudy; Sergey Golovanov
> Subject: RE: ICMP showing encapsulation failed
>
> I checked the following items and they all seemed OK:
>
> 1. all trunk interfaces are "trunking" under "show int trun"
> 2. vlan 30 is configured on both CAT1 and CAT2
> 3. all used interfaces are "FWD" under "show span vlan 30"
> 4. all interfaces are full duplex and 100 mbps under "show interface"
>
> I turned on "deb arp" on devices and noticed that:
> 1. when R4 is pinging CAT1, CAT1 does not see any ARP request
> 2. when CAT1 is pinging R4, R4 sees the ARP requests and responds, but
> CAT1 does not see the response comes back
>
> This seems that communication from R4 to CAT1 is blocked somehow. Any
> suggestions?
>
> I also put in a temporary vlan 30 interface on CAT2, R4 can ping CAT2,
> R3 can be ping CAT1, but just not across the trunk link which seems to
> be cause. But I don't know why this is happening...
>
> Thanks in advance ....
>
>
> -----Original Message-----
> From: Muizebelt Danny [mailto:Danny.Muizebelt@osiatis.at]
> Sent: Thursday, January 25, 2007 1:12 AM
> To: Michael Zuo; ccielab groupstudy
> Subject: RE: ICMP showing encapsulation failed
>
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA256
>
> I think you didn't get an arp resolution for the 172.16.34.4 address,
> that's why the encapsulation failed because there is no L3 to L2
> mapping.
>
> The reason why there is no arp resolution could be a problem with your
> trunk, is it up? Is vlan 30 defined on both switches? Is the spanning
> tree working properly?
>
> Another thing I wanted to point out, if you statically configure
duplex
> settings on one side and leave the other side on auto then the auto
side
> will fall back to default half-duplex. Statically configuring duplex
> settings switches off the auto negotiation. So either both sides on
auto
> or both statically configured.
>
>
> Danny Muizebelt
> CCIE #17353
>
> - -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Michael Zuo
> Sent: Donnerstag, 25. Jdnner 2007 08:22
> To: ccielab groupstudy
> Subject: ICMP showing encapsulation failed
>
> Hi group,
>
>
>
> I am scratching my head on this one (probably something basic), please
> help! And thanks in advance....
>
>
>
>
>
>
R3(f0/1)---------(f0/4)CAT1(f0/14)-----------(f0/14)CAT2(f0/5)----------
> - -----R4(f0/0)
>
>
>
> When I ping from R3 to R4, I get encapsulation failed message on R3:
>
>
>
> R3(config-if)#do ping 172.16.34.4
>
>
>
> Type escape sequence to abort.
>
> Sending 5, 100-byte ICMP Echos to 172.16.34.4, timeout is 2 seconds:
>
>
>
> 2d07h: IP: tableid=0, s=172.16.34.3 (local), d=172.16.34.4
> (FastEthernet0/1), ro
>
> uted via RIB
>
> 2d07h: IP: s=172.16.34.3 (local), d=172.16.34.4 (FastEthernet0/1), len
> 100, send
>
> ing
>
> 2d07h: IP: s=172.16.34.3 (local), d=172.16.34.4 (FastEthernet0/1), len
> 100, enca
>
> psulation failed.
>
> 2d07h: IP: tableid=0, s=172.16.34.3 (local), d=172.16.34.4
> (FastEthernet0/1), ro
>
> uted via RIB
>
> 2d07h: IP: s=172.16.34.3 (local), d=172.16.34.4 (FastEthernet0/1), len
> 100, send
>
> Ing
>
>
>
>
>
>
>
> Configuration:
>
>
>
> R3:
>
> =======
>
> R3(config-router)#do sh run int f0/1
>
> Building configuration...
>
>
>
> Current configuration : 96 bytes
>
> !
>
> interface FastEthernet0/1
>
> ip address 172.16.34.3 255.255.255.0
>
> duplex auto
>
> speed auto
>
> end
>
>
>
> R3(config-router)#
>
>
>
>
>
> CAT1:
>
> ========
>
> CAT1(config)#do sh run int f0/4
>
> Building configuration...
>
>
>
> Current configuration : 97 bytes
>
> !
>
> interface FastEthernet0/4
>
> switchport access vlan 30
>
> switchport mode access
>
> duplex full
>
> end
>
>
>
> CAT1(config)#do sh run int f0/14
>
> Building configuration...
>
>
>
> Current configuration : 137 bytes
>
> !
>
> interface FastEthernet0/14
>
> switchport trunk encapsulation dot1q
>
> switchport trunk allowed vlan 1,20,30,40
>
> switchport mode trunk
>
>
>
> CAT1(config-if)#do sh run int vlan 30
>
> Building configuration...
>
>
>
> Current configuration : 63 bytes
>
> !
>
> interface Vlan30
>
> ip address 172.16.34.10 255.255.255.0
>
> end
>
>
>
>
>
> CAT2:
>
> CAT2(config-if)#do sh run int f0/5
>
> Building configuration...
>
>
>
> Current configuration : 97 bytes
>
> !
>
> interface FastEthernet0/5
>
> switchport access vlan 30
>
> switchport mode access
>
> duplex full
>
> end
>
>
>
> CAT2(config-if)#do sh run int f0/14
>
> Building configuration...
>
>
>
> Current configuration : 137 bytes
>
> !
>
> interface FastEthernet0/14
>
> switchport trunk encapsulation dot1q
>
> switchport trunk allowed vlan 1,20,30,40
>
> switchport mode trunk
>
> end
>
>
>
> CAT2(config-if)#
>
>
>
>
>
> R4
>
> =======
>
> R4(config-router)#do sh run int f0/0
>
> Building configuration...
>
>
>
> Current configuration : 96 bytes
>
> !
>
> interface FastEthernet0/0
>
> ip address 172.16.34.4 255.255.255.0
>
> duplex auto
>
> speed auto
>
> end
>
>
>
> R4(config-router)#
>
>
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