Routing... I don't understand this not working.

Michael Durham · ‎01-15-2013

If I set up two routers, connect them, set the IP addresses, I can ping each other. But if I set up two 3550 Layer 3 switches as router ports, I cannot ping each other.

SWITCH ONE:

interface FastEthernet0/6

no switchport

ip address 10.93.5.1 255.255.255.252

spanning-tree portfast

SWITCH TWO:

interface FastEthernet0/1

no switchport

ip address 10.93.5.2 255.255.255.252

spanning-tree portfast

I have even added the following IP routes:

ip route 10.93.5.0 255.255.255.252 10.93.5.2

and I have also tried

ip route 10.93.5.0 255.255.255.252 fa0/6

of course I put the revers routes on the other switch. I jsut want to set up two 3550 switches to talk to each other as though they wer both just a router. Can this be done or does one of them have to be set up as a trunk port?

johnlloyd_13 · ‎01-15-2013

Hi,

Is 'ip routing' enabled on your L3 switches?

Sent from Cisco Technical Support iPad App

kcnajaf · ‎01-15-2013

Hi Michael,

Looks like you have assigned the ip address to the physcial interface. In this case you will have to connect these two interface back to back to make it ping each other (i.e Fas 0/6 of SW1 to Fas 0/1 of SW2). You dont need any static route for this to work when you are directly connected.

On other hand you can remove these ip address from physical interface ans assign to to switched virtual interface (SVI's) and then connect the switch back to back and configure them as access port. A typical configuration for your setup will be like as below. In order to maje the device act as router you need to enable routing first with ip routing command.

SWITCH ONE

ip routing

!

interface FastEthernet0/6

no ip address 10.93.5.1 255.255.255.252

!

int vlan 10

ip address 10.93.5.1 255.255.255.252

!

vlan 10

!

int Fas 0/6

switch port

switch port access vlan 10

!

SWITCH TWO

ip routing

!

interface FastEthernet0/1

no ip address 10.93.5.2 255.255.255.252

!

int vlan 10

ip address 10.93.5.2 255.255.255.252

!

vlan 10

!

interface FastEthernet0/1

switchport

ip address 10.93.5.2 255.255.255.252

Since both switches are on the same vlan you dont need to configure any routes on the switchs.

Give a try and check how it goes.

Hope that helps

Regards

Najaf

Please rate when applicable or helpful !!!

Michael Durham · ‎01-15-2013

Yes, IP routing is enabled. Yes they are connected back-to-back via a crossover cable. But the do not ping each other. There are VLANs addigned top toher ports on the switch. I was trying to not ise VLANS to connect these two switches.

Any idea why they can't ping each other? It doesn't make since to me.

milan.kulik · ‎01-15-2013

Hi,

do the switches see each other via CDP on those ports?

What about ARP cache?

Do you see the other switch IP address and corresponding MAC in it?

HTH,

Milan

glen.grant · ‎01-15-2013

If you do a "show int status" on both switches do both sides show connected ? Also make sure you see the other as a cdp neighbor. Otherwise I dont see a reason why it shouldn't work.

Michael Durham · ‎01-15-2013

sh ip int bri on both switches show the interfaces up up. So full conectivity is there.

sh arp results:

Internet 10.93.5.2 0 Incomplete ARPA

Internet 10.93.5.1 - 0013.7fe0.4080 ARPA FastEthernet0/6

and its the other way on the other switch.

CDP, they do not see each other.

NOTE: When I had these switches connected and using VLAN'a, the same interfaces could see each other. I wonder if the 3550 switches cannot operate like a real router?

glen.grant · ‎01-15-2013

If you dont see cdp then that's an issue unless cdp was specifically turned off. There is no restriction on using routed ports on the 3550 , something else going on seeing you dont see cdp neighbor and you can't ping a directly attached interface.

Michael Durham · ‎01-15-2013

I AM SUCH AN ID10T!!!!

Please accept my apology, I had the second switch plugged into interface fa0/7 on switch 1 but did all my config on fa0/6. UGGGG. It does work correctly when you configure the correct port.

Thanks for helping!

Michael

PS: MORE COFFEE!!!!

Richard Burts · ‎01-15-2013

Michael

I am glad that you worked out the solution to your own problem. +5 to you for posting back to the forum to explain what the problem was. This may server as an example to other readers of the forum that sometimes it is important to check for really basic things, such as the question is the physical connection the same as the interface that I am configuring.

HTH

Rick

HTH

Rick