topic RE: creating double tagged packet from untagged input and vice versa in ExtremeSwitching (EXOS/Switch Engine)

creating double tagged packet from untagged input and vice versa

sumeet — Thu, 13 Jul 2017 09:42:00 GMT

hi
i am using extreme x460-24t switch.
My aim is to feed packet (say ping) from laptop to port , say IN , and get double tagged packet out from another port (say OUT). Also double tagged packet is fed in OUT and should come out untagged from IN.
Example -
My laptop is connected to port 1 of switch . laptop has ip 10.0.0.2/24 . I run ping 10.0.0.1 in laptop.
I want switch to put inner vlan tag 100 and outer vlan tag 500 on this ping packet.
So the packet that comes out of port 5 has outer vlan tag 500 and inner vlan tag 100 .

I am trying this setup currently (Don't know if it is the right way)
Port 1 is set untagged for vlan 100 .
port 2 is set tagged for vlan 100.
port 3 is connected to port 2 via ethernet cable.(feeding one port of switch from another , is that ok ? )
We have vman named five_hundred set for tag 500.
port 3 is added as untagged member of this vman.
port 4 is tagged member of this vman .
So , I should get double tagged packets out from port 4.
And , double tagged packets fed to port 4 should come out unatgged from port 1.

Thanks .

RE: creating double tagged packet from untagged input and vice versa

Nick_Yakimenko — Thu, 13 Jul 2017 11:49:00 GMT

vman should be ued for inner tag use vlan for outer tag

RE: creating double tagged packet from untagged input and vice versa

Stephane_Grosj1 — Thu, 13 Jul 2017 12:34:00 GMT

Hi,

since 15.3.2 VMAN double-tag in a single pass is supported, with the following command:

configure vman add ports [ | all] untagged {port-cvid }
As per the User Guide:

"The VMAN double tag feature adds an optional port CVID parameter to the existing untagged VMAN
port configuration. When present, any untagged packet received on the port will be double tagged
with the configured port CVID and SVID associated with the VMAN. Packets received with a single
CVID on the same port will still have the SVID added. As double tagged packets are received from
tagged VMAN ports and forwarded to untagged VMAN ports, the SVID associated with the VMAN is
stripped. Additionally, the CVID associated with the configured Port CVID is also stripped in the same
operation.

Much like the CVIDs configured as part of the CEP feature, the configured Port CVID is not represented
by a VLAN within EXOS. The implication is that protocols and individual services cannot be applied to
the Port CVID alone. Protocols and services are instead applied to the VMAN and/or port as the VMAN
represents the true layer-2 broadcast domain. Much like regular untagged VMAN ports, MAC FDB
learning occurs on the VMAN, so duplicate MAC addresses received on multiple CVIDs that are mapped
to the same VMAN can be problematic. Even when the additional Port CVID is configured, the port still
has all of the attributes of a regular untagged VMAN port. This means that any single c-tagged packets
received on the same port will have just the SVID associated with the VMAN added to the packet.
Likewise, any egress packet with a CVID other than the configured Port CVID will have the SVID
stripped."

RE: creating double tagged packet from untagged input and vice versa

Karthik_Mohando — Thu, 13 Jul 2017 17:01:00 GMT

adding to Stephane's post
This Article has the steps on how to configure VMAN.
https://gtacknowledge.extremenetworks.com/articles/How_To/How-to-configure-a-VMAN-in-EXOS