CISCO Nexus 3048 as Access and CISCO 3548 as Core Switch (Inter VLAN Routing)

[BaberS]

Hi CISCO community

Maybe this is a basic question and would have been discussed before but I could not find relevant answers as per my own scenario. Let me explain topology and configuration and what I want to achieve

Topology 

=========

2x CISCO 3548 switches connected to each other via two fiber cables

1x CISCO 3048 switch connected to these core switches. Two fibers going to each core switch.

Configuration

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

On two core switches I have configured vPC and it is working fine. In addition to that I have configured multiple VLANs on these two core switches and given them IPs from different subnets. Also HSRP is configured. Example given below

VLAN 213 : 172.22.22.253 (Core-1)

VLAN 213 : 172.22.22.254 (Core-2)

Virtual IP : 172.22.22.1

Enabled Features : interface-vlan, hsrp-engine, vpc, udld

VLAN 221 : 172.22.30.253 (Core-1)

VLAN 221:  172.22.30.254 (Core-2)

Virtual IP : 172.22.30.1

On Access layer CISCO 3048, I have configured VLAN 213 and 221 without IP. Interface-vlan feature is disabled. 

Problem

==========

I want to PING an IP 172.22.22.1 from Access Switch which I cannot do. Reason seems obvious that there is no route to the subnet.

MCR-ESW01(config)# show ip route
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

In catalyst series of switches, I used to add default-gateway (VIP of the managment VLAN) and all set go. I have tried to add route using "ip route" command but unabel to acess any of the VLANs interface IPs on core switches.

Let me know if you guys need more info on configurations of these three switches.

Thanks in advance.

Baber

[Deepak Kumar]

Hi,

IP default gateway and at list one SVI must have IP  on access switch to ping your core switch IP or other IP on your network.

Regards,

Deepak Kumar

[BaberS]

Dear Deepak

Can you please tell me the exact command to setup default gateway on the 3048 switch. I couldn't find "ip default-gateway" command which is normally available on other OS images

Software BIOS: version 1.4.0

loader: version N/A kickstart: version 6.0(2)U6(9)

system: version 6.0(2)U6(9)

Power Sequencer Firmware: Module 1: version v4.4

BIOS compile time: 12/09/2013

kickstart image file is: bootflash:///n3000-uk9-kickstart.6.0.2.U6.9.bin

kickstart compile time: 1/7/2017 1:00:00 [01/07/2017 14:01:22]

system image file is: bootflash:///n3000-uk9.6.0.2.U6.9.bin

[BaberS]

I have following route but even then I am unable to ping any other VLAN IP e.g 172.22.22.253 or VIP 172.22.22.1

MCR-ESW01(config-if)# show ip route

IP Route Table for VRF "default" '*' denotes best ucast next-hop '**' denotes best mcast next-hop '[x/y]' denotes [preference/metric] '%' in via output denotes VRF 172.22.30.0/24, ubest/mbest: 1/0, attached *via 172.22.30.20, Vlan221, [0/0], 00:00:05, direct 172.22.30.20/32, ubest/mbest: 1/0, attached *via 172.22.30.20, Vlan221, [0/0], 00:00:05, local

[Deepak Kumar]

HI,

in the Nexus switches, there will no default gateway command. It is the default route.

  ip route 0.0.0.0/0 XX.XX.XX.XX

Regards,

Deepak Kumar

[BaberS]

MCR-ESW01(config)# show ip static-route
Static-route for VRF "default"(1)
IPv4 Unicast Static Routes:
0.0.0.0/0, configured nh: 172.22.30.0/24
(not installed in urib)
rnh(installed in urib)



MCR-ESW01(config)# ping 172.22.30.1
PING 172.22.30.1 (172.22.30.1): 56 data bytes
ping: sendto 172.22.30.1 64 chars, No route to host
Request 0 timed out
ping: sendto 172.22.30.1 64 chars, No route to host
Request 1 timed out
ping: sendto 172.22.30.1 64 chars, No route to host

--- 172.22.30.1 ping statistics ---
3 packets transmitted, 0 packets received, 100.00% packet loss

[Deepak Kumar]

Hi, 

Please share configuration of nexus switch.

Regards,

Deepak Kumar

[BaberS]

Please find attached file of 3048 (Access Switch) config

[BaberS]

Hi Deepak,

Did you get a chance to look at the config I sent yesterday.

[Deepak Kumar]

Hi,

I just looked at the configuration and found that there is no IP address under any VLAN or interface. You have to configure one IP address under the SVI so the switch can get source IP from SVI and forward the packet to gateway or destination. 

Regards,

Deepak Kumar

[BaberS]

Hi Deepak

Later I also gave IP to one of the VLANs as below. I am able to PING to network 172.22.30.0 but not to any other VLAN (which is on the core switch).

interface Vlan221
no shutdown
no ip redirects
ip address 172.22.30.20/24
==================================

MCR-ESW01(config-if)# show ip route
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

172.22.30.0/24, ubest/mbest: 1/0, attached
*via 172.22.30.20, Vlan221, [0/0], 00:27:55, direct
172.22.30.20/32, ubest/mbest: 1/0, attached
*via 172.22.30.20, Vlan221, [0/0], 00:27:55, local

===========================
Able to PING to 172.22.30.0 network's IP

MCR-ESW01(config-if)# ping 172.22.30.1
PING 172.22.30.1 (172.22.30.1): 56 data bytes
64 bytes from 172.22.30.1: icmp_seq=0 ttl=254 time=13.141 ms
64 bytes from 172.22.30.1: icmp_seq=1 ttl=254 time=2.489 ms
64 bytes from 172.22.30.1: icmp_seq=2 ttl=254 time=2.5 ms
64 bytes from 172.22.30.1: icmp_seq=3 ttl=254 time=2.229 ms
64 bytes from 172.22.30.1: icmp_seq=4 ttl=254 time=2.249 ms

--- 172.22.30.1 ping statistics ---
5 packets transmitted, 5 packets received, 0.00% packet loss
round-trip min/avg/max = 2.229/4.521/13.141 ms

However, cannot PING to any other subnet.

MCR-ESW01(config-if)# ping 172.22.22.1
PING 172.22.22.1 (172.22.22.1): 56 data bytes
ping: sendto 172.22.22.1 64 chars, No route to host
Request 0 timed out
ping: sendto 172.22.22.1 64 chars, No route to host
Request 1 timed out



Regards
Baber

[Deepak Kumar]

Hi,

I can see "No route" error in ping command. Means you didn't assign the correct route on the switch?

Can you attach a system on VLAN 230 on this switch and ping the other VLANs? Make sure you have to assign default gateway as your core switch SVI interface IP in the switch.

If you can ping the other VLANs using your systems then you have to check your default route which you configured on this switch. 

Please share some details as:

What is IP assigned to your core switch SVI 230?

What is default route configuration on this switch?

Can you ping destination IP which you configured in default route?

Regards,

Deepak Kumar

[BaberS]

Dear Deepak

From my laptop connected to Access SW Port eth1/1 (assigned to VLAN 221), I am able to ping all other VLANs. However, if I try to ping from Access Switch itself, I cannot do that. One reason is obvious that there is no default route configuration on this switch and this is the problem.

How to create default route on the access switch so that this switch is able to ping to other VLANs on the attached core switches. Can you tell me the exact command for that matter.

P.S: Attached config from one of the core switches.

Regards

Baber 

[Deepak Kumar · Accepted solution]

Hi, 

Only you are missing the default route on Nexus switch:

The command must be like this:

ip route 0.0.0.0/0 VLAN <X> <VLAN Virtual IP>

X= VLAN ID number.

VLAN Virtual IP = Destination (Core switch) VIP of particular VLAN.

Regards,

Deepak Kumar

[BaberS]

Dear Deepak

Thanks for your tip. This issue of interconnectivity between Core and Access switches is resolved by setting default route as per below.

ip route 0.0.0.0/0 172.22.30.1
where 172.22.30.1 is VIP of our Management VLAN.

All sorted out.

Thanks
Baber