Re: Catalyst 3750 with 2 vlans. Only vlan1 drop packet when ping

On Jun 28, 2:28 pm, Trendkill <jpma...@xxxxxxxxx> wrote:
On Jun 27, 9:12 pm, Trendkill <jpma...@xxxxxxxxx> wrote:



On Jun 27, 9:00 pm, hamster <wongbe...@xxxxxxxxx> wrote:

Hi all, I have problem with vlan 1 on the Cisco Catalyst 3750 switch.

I created vlan140 on the switch. There is only one port connected to
up link. I could ping the ip on vlan140 without droping package, but
when I ping to the ip on vlan1, about 10% come back with "Request
timed out."

I have checked the interface error on both side of the cable, they are
all zero.
I tried different ip addresses for vlan1 and even replace the cable,
no luck.

Could anybody suggest what else I can try?

Many thanks.

Here is the configuration which I believe is relevant:
==========================================
no aaa new-model
system mtu routing 1500
ip subnet-zero
ip routing
!
no file verify auto
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
!
vlan internal allocation policy ascending

interface Vlan1
ip address 10.0.2.247 255.255.252.0
standby 140 ip 10.0.0.117
standby 140 preempt delay minimum 60
!
interface Vlan140
ip address 10.0.140.16 255.255.252.0
standby 141 ip 10.0.140.1
standby 141 preempt delay minimum 60
!
ip default-gateway 10.0.0.1
ip classless
ip route 0.0.0.0 0.0.0.0 10.0.0.1
ip http server
no ip http secure-server
=====================================

You have HSRP configured....where is the other hsrp peer? Are these
VLAN's trunked? Anything in the logs about 'standby' changes? If you
just have it configured and there is no other switch/router, then this
should work fine. But I am guessing that you have another core and we
need to see that config and log as well.

Do me a favor and send me the configs for both routers. You may want
to turn logging on at an informational level, in case HSRP is losing
its neighbor and your timeout is causing it to failover for a specific
time. Are you pinging the hsrp vlan 1 address, or the specific
switch's address in vlan 1? Can you ping both and see if both fail or
if it is just one? If it is just one, it tends to look like an HSRP
or connectivity issue between your two switches. If both fail, then
it sounds like we have another issue. Also, are you able to always
ping vlan 140's interface with no problems? Is 140 trunked over to
the other switch? If not, how does the other switch know how to get
back to this switch to reply to the node's ping?

In short, you can either trunk all vlans between your two cores (cores
= routers that own all vlans, usually from a layer 2 and layer 3
perspective), or you can have vlans on different switches, and have
them advertise the networks between one another. What I see here is a
hybrid model that will not work. If you want to do the second option,
you need to turn up a routing protocol or statics to let the first
switch/router know about the new vlan (140), or you need to trunk/
connect 140 directly to avoid multi hop standby (should work, just not
a good practice).

.

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