PING Failure - I am at a loss!

visitor68 · ‎09-07-2015

Folks -

The setup is simple.

I have 2 Dell switches connected in a VLT, like Cisco's VPC.
Dual-homed to the Dell switches is a Cisco L3 switch using a split LAG - Po1. The Cisco connects to Te0/6 on each Dell switch.
Each Dell switch has an SVI for VLAN 20 configured - a /29 VLAN..192.168.20.1 on Dell#1 and 192.168.20.2 on Dell#2
Cisco switch has a L3 Port-channel (Po1) with an IP address on the Po1 interface of 192.168.20.3/29

As you can see below, all interfaces on all 3 switches are up - physical, logical, port-channels, vlans, etc - everything! BUT I CAN'T PING! UGH!!!! :-) The Cisco switch can ping itself, but not the Dell switches. And the Dell switches can ping themselves and each other, but not the Cisco. See PING failures below along with output of a 'show debug IP packet'

HELP!!!! LOL

[By the way, be mindful that I tried a different setup, too. Instead of a L3 Port-channel on the Cisco switch, as you see below, I configured an SVI for VLAN 20, and applied an IP address to the VLAN interface. In that case, the port-channel was a L2 channel in access mode, where VLAN 20 was allowed on it. I got the exact same result there, too]

!
CISCO L3 SWITCH

interface FastEthernet0/13

description To Dell #1 Switch Te0/6
no switchport
no ip address
channel-group 1 mode on
end

Cisco-Router#
Cisco-Router#
Cisco-Router#sh run int fa0/14
Building configuration...

Current configuration : 89 bytes
!
interface FastEthernet0/14

description To Dell #2 Switch Te0/6
no switchport
no ip address
channel-group 1 mode on
end

Cisco-Router#
Cisco-Router#sh run int po1
Building configuration...

Current configuration : 87 bytes
!
interface Port-channel1
no switchport
ip address 192.168.20.3 255.255.255.248
end

Cisco-Router#
Cisco-Router#
Cisco-Router#sh int fa0/13 | in line
FastEthernet0/13 is up, line protocol is up (connected)
Cisco-Router#
Cisco-Router#sh int fa0/14 | in line
FastEthernet0/14 is up, line protocol is up (connected)
Cisco-Router#
Cisco-Router#sh int po1 | in line
Port-channel1 is up, line protocol is up (connected)
Cisco-Router#
Cisco-Router#

PING AND IP DEBUG

00:36:14: IP: s=192.168.20.3 (local), d=192.168.20.2 (Port-channel1), len 100, sending
00:36:14: IP: s=192.168.20.3 (local), d=192.168.20.2 (Port-channel1), len 100, sending full packet.
00:36:15: IP: s=192.168.20.2 (Port-channel1), d=224.0.0.5, len 68, rcvd 0
00:36:16: IP: s=192.168.20.3 (local), d=192.168.20.2 (Port-channel1), len 100, sending
00:36:16: IP: s=192.168.20.3 (local), d=192.168.20.2 (Port-channel1), len 100, sending full packet.
00:36:18: IP: s=192.168.20.3 (local), d=192.168.20.2 (Port-channel1), len 100, sending
00:36:18: IP: s=192.168.20.3 (local), d=192.168.20.2 (Port-channel1), len 100, sending full packet.
00:36:20: IP: s=192.168.20.3 (local), d=192.168.20.2 (Port-channel1), len 100, sending
00:36:20: IP: s=192.168.20.3 (local), d=192.168.20.2 (Port-channel1), len 100, sending full packet.
00:36:22: IP: s=192.168.20.3 (local), d=192.168.20.2 (Port-channel1), len 100, sending
00:36:22: IP: s=192.168.20.3 (local), d=192.168.20.2 (Port-channel1), len 100, sending full packet.
Success rate is 0 percent (0/5)
Cisco-Router#

================================================================================================

DELL SWITCH # 1

Dell#1#sh run int te0/6
!
interface TenGigabitEthernet 0/6
description to Cisco port 13/Po1
no ip address
no shutdown
Dell#1#
Dell#1#
Dell#1#sh run int po1
!
interface Port-channel 1
no ip address
switchport
channel-member TenGigabitEthernet 0/6
vlt-peer-lag port-channel 1
no shutdown
Dell#1#
Dell#1#
Dell#1#
Dell#1#sh run int vlan 20
!
interface Vlan 20
description OSPF PEERING VLAN
ip address 192.168.20.1/29
untagged Port-channel 1
no shutdown
Dell#1#
Dell#1#
Dell#1#
Dell#1#
Dell#1#sh int te0/6 | find line
TenGigabitEthernet 0/6 is up, line protocol is up
Port is part of Port-channel 1
Description: to Cisco port 1/Po1
Hardware is DellEth, address is 90:b1:1c:f4:2c:bd
Dell#1#
Dell#1#
Dell#1#
Dell#1#sh int po1
Port-channel 1 is up, line protocol is up
Hardware address is 90:b1:1c:f4:2c:bd, Current address is 90:b1:1c:f4:2c:bd
Interface index is 1090977793
Minimum number of links to bring Port-channel up is 1
Internet address is not set
Mode of IPv4 Address Assignment : NONE
DHCP Client-ID :90b11cf42cbd
MTU 1554 bytes, IP MTU 1500 bytes
LineSpeed 100 Mbit
Members in this channel: Te 0/6(U)
Dell#1#
Dell#1#
Dell#1#
Dell#1#
Dell#1#sh int vlan 20
Vlan 20 is up, line protocol is up
Description: OSPF PEERING VLAN
Address is 90:b1:1c:f4:2c:bd, Current address is 90:b1:1c:f4:2c:bd
Interface index is 1091010580
Internet address is 192.168.20.1/29

==============================================================================================================

DELL SWITCH #2

Dell#2#
Dell#2#sh run int te0/6
!
interface TenGigabitEthernet 0/6

description to Cisco port 14/Po1
no ip address
no shutdown
Dell#2#
Dell#2#
Dell#2#
Dell#2#sh run int po1
!
interface Port-channel 1
no ip address
switchport
channel-member TenGigabitEthernet 0/6
vlt-peer-lag port-channel 1
no shutdown
Dell#2#
Dell#2#
Dell#2#
Dell#2#sh run int vlan 20
!
interface Vlan 20
description OSPF PEERING VLAN
ip address 192.168.20.2/29
untagged Port-channel 1
no shutdown
Dell#2#
Dell#2#
Dell#2#
Dell#2#
Dell#2#sh int te0/6
TenGigabitEthernet 0/6 is up, line protocol is up
Port is part of Port-channel 1
Hardware is DellEth, address is 90:b1:1c:f4:29:f3
Dell#2#
Dell#2#
Dell#2#
Dell#2#sh int po1
Port-channel 1 is up, line protocol is up
Hardware address is 90:b1:1c:f4:29:f3, Current address is 90:b1:1c:f4:29:f3
Interface index is 1090977793
Minimum number of links to bring Port-channel up is 1
Dell#2#
Dell#2#
Dell#2#
Dell#2#sh int vlan 20
Vlan 20 is up, line protocol is up
Description: OSPF PEERING VLAN
Address is 90:b1:1c:f4:29:f3, Current address is 90:b1:1c:f4:29:f3
Interface index is 1091010580
Internet address is 192.168.20.2/29

PING AND IP DEBUG

Dell#2#01:43:49 : IP: s=192.168.20.1 (Vl 20), d=224.0.0.5, len 68, rcvd proto=89
term mon01:43:50 : IP: s=192.168.20.2 (local), d=224.0.0.5 (Vl 20), len 68, sending proto=89
ping 192.168.20.3

Type Ctrl-C to abort.

Sending 5, 100-byte ICMP Echos to 192.168.20.3, timeout is 2 seconds:
01:43:56 : IP: s=192.168.20.2 (local), d=192.168.20.3 (Vl 20), len 100, sending
    ICMP type=8, code=0
01:43:56 : IP: s=192.168.20.2, d=192.168.20.3 (Vl 20), len 100, ethernet encapsulation failed: ARP not resolved, destination MAC not available
    ICMP type=8, code=0
.01:43:58 : IP: s=192.168.20.2 (local), d=192.168.20.3 (Vl 20), len 100, sending
    ICMP type=8, code=0
01:43:58 : IP: s=192.168.20.2, d=192.168.20.3 (Vl 20), len 100, ethernet encapsulation failed: ARP not resolved, destination MAC not available
    ICMP type=8, code=0
01:43:59 : IP: s=192.168.20.1 (Vl 20), d=224.0.0.5, len 68, rcvd proto=89
.01:44:00 : IP: s=192.168.20.2 (local), d=192.168.20.3 (Vl 20), len 100, sending
    ICMP type=8, code=0
01:44:00 : IP: s=192.168.20.2, d=192.168.20.3 (Vl 20), len 100, ethernet encapsulation failed: ARP not resolved, destination MAC not available
    ICMP type=8, code=0
01:44:00 : IP: s=192.168.20.2 (local), d=224.0.0.5 (Vl 20), len 68, sending proto=89
.01:44:02 : IP: s=192.168.20.2 (local), d=192.168.20.3 (Vl 20), len 100, sending
    ICMP type=8, code=0
01:44:02 : IP: s=192.168.20.2, d=192.168.20.3 (Vl 20), len 100, ethernet encapsulation failed: ARP not resolved, destination MAC not available
    ICMP type=8, code=0
.01:44:04 : IP: s=192.168.20.2 (local), d=192.168.20.3 (Vl 20), len 100, sending
    ICMP type=8, code=0
01:44:04 : IP: s=192.168.20.2, d=192.168.20.3 (Vl 20), len 100, ethernet encapsulation failed: ARP not resolved, destination MAC not available
    ICMP type=8, code=0
.
Success rate is 0.0 percent (0/5)

Richard Bradfield · ‎09-07-2015

I don't think you can do what you are trying to do, you are splitting a port channel between two switches.

How about setting up individual links say

on Cisco port fa0/13 192.168.20.1/30 to Dell1 192.168.20.2/30 on Te0/6

and Cisco port fa0/14 192.168.20.5/30 to Dell2 192.168.20.6/30 on Te0/6

forget about port channels

HTH

Richard.

visitor68 · ‎09-11-2015

Guys, it is interesting, isn't it? Nonetheless, you can deploy this setup and have it work fine. I know because I figured out what was wrong with it. Remember, it didnt work using a L2 port channel with SVIs on the Cisco switch either.

So what was the problem? Dell VLT did not support PVST+ until a certain code version - FTOS 9.7. I had forgotten that and deployed PVST. Changed it to RSTP and voila!, everything works and is rock stable.

Thanks for your inputs though...I appreciate it

visitor68 · ‎09-11-2015

Richard, yes, /30s are definitely an option, too.

Steve Fuller · ‎09-08-2015

Hi,

You stated "[By the way, be mindful that I tried a different setup, too. Instead of a L3 Port-channel on the Cisco switch, as you see below, I configured an SVI for VLAN 20, and applied an IP address to the VLAN interface. In that case, the port-channel was a L2 channel in access mode, where VLAN 20 was allowed on it. I got the exact same result there, too]"

I'm not sure how a Layer-2 port-channel on one device is going to communicate with a Layer-3 port-channel on another.

Don't shoot the messenger, but given we're already into a multi-vendor environment, we're probably best off not pushing our luck and trying different (and probably incompatible) technologies as well.

As both the Cisco and Dell support IEEE 802.1Q and 802.1AX, my personal view is that you'd be better off going back to using Layer-2 port-channel on the Cisco and figure out why things didn't work in that setup. At least then we're starting from a known position i.e., both switches running compatible technologies.

You don't mention the Cisco switch model, but presumably you can configure the port-channel as a Layer-2 trunk with all VLANs allowed and enable LACP i.e., channel-group <group> mode active. You can then configure the Dell VLT switch pair with port-channel-protocol lacp and port-channel <group> mode active. If we focus on ensuring we have a good Layer-2 path up with the switches talking LACP to each other, then we can try and figure out any Layer-3 issue after that.

Regards