Posted on May 31, 2021 6:19 am
 |  Asked by Dmitry Zhukov
Print Friendly, PDF & Email

Hello, I need to build an unusual schema.
PC1 => 14 port Arista Switch (Vlan20, access port) => 7 port Arista (Vlan20, access port)=> loop (direct link) => 8 port Arista (Vlan10, access port) => 18 port Arista (Vlan10, access port) => PC2
In cisco packet tracer I can do it if changed the loop to a simple switch. Please look at attached image 1.

But in Arista this schema don’t work. look at attached image 2.
I started tcpdump on Arista ports 7,8,14,18. If I send ICMP request from PC1. I can see requests in tcpdump on 14, 7, 8 ports. But on 8 port empty. If I send a request from PC2 to PC1, I see a request on 18 port and after nothing.
Looks like 18 and 8 port in different VLANs, but it is wrong.

show vlan
VLAN Name Status Ports
—– ——————————– ——— ——————————-
1 default active Cpu, Et1, Et2, Et5, Et13, Et16
10 VLAN10 active Et8, Et18
20 VLAN20 active Et7, Et14
33 test-vlan active
100 VLAN0100 active

Posted by Vijay Kumar
Answered on May 31, 2021 6:29 am

Hi Dmitry,

Can you please also check the STP forwarding state of these ports and collect the output of following (start the ping then collect)?

Show spanning | no-more

Show mac address-table | no more

If switch is running default STP mode (MSTP) then I am expecting the Port et8 to be blocked. Spanning-tree mode to Rapid-pvst might help in this scenario.




Post your Answer

You must be logged in to post an answer.