EXOS what is VR?


Userlevel 3
Hi,

I have experience on Enterasys gears. We just get our first Extreme devices, X440. I am reading jump start documentation. One thing I can not undestand is VR terminology. Simply what is it for? I know and understand it is "virtual router" but what is it used for. There is no VR like feature on EOS, cisco or HP switches that I used.

If I use VR default for all L3 vlans, it means it will work like EOS configuration as I understand. So what can I gain if I use different VRs for different vlan interfaces?

Thanks.

3 replies

Userlevel 6
Hi!

From User Guide:
The ExtremeXOS software supports virtual routers (VRs). This capability allows a single physical switchto be split into multiple VRs. This feature separates the traffic forwarded by a VR from the traffic on a
different VR.
Each VR maintains a separate logical forwarding table, which allows the VRs to have overlapping IP
addressing. Because each VR maintains its own separate routing information, packets arriving on one
VR are never switched to another.

Also there is VRF:
VRFs are created as children of user VRs or VR-Default, and each VRF supports Layer 3 routing andforwarding. The routing tables for each VRF are separate from the tables for other VRs and VRFs, so
VRFs can support overlapping address space. The primary differences between VRs and VRFs are:
• For each routing protocol added to a VRF, only one process is started in the user VR and VRF. The
VRF protocol operates as one instance of the parent VR protocol, and additional child VRFs operate
as additional instances of the same parent VR protocol process. VRFs allow a protocol process
running in the parent VR to support many virtual router instances.
• ExtremeXOS supports up to 63 VRs and up to many more VRFs. (For the maximum number of
supported VRFs, see the ExtremeXOS Release Notes.)

In User Guide a lot of clear information about that.

User Guide you can download from here - http://www.extremenetworks.com/support/documentation

Or for older versions EXOS here - http://www.extremenetworks.com/support/documentation-archives

Thank you!
Userlevel 3
Alexandr P wrote:

Hi!

From User Guide:
The ExtremeXOS software supports virtual routers (VRs). This capability allows a single physical switchto be split into multiple VRs. This feature separates the traffic forwarded by a VR from the traffic on a
different VR.
Each VR maintains a separate logical forwarding table, which allows the VRs to have overlapping IP
addressing. Because each VR maintains its own separate routing information, packets arriving on one
VR are never switched to another.

Also there is VRF:
VRFs are created as children of user VRs or VR-Default, and each VRF supports Layer 3 routing andforwarding. The routing tables for each VRF are separate from the tables for other VRs and VRFs, so
VRFs can support overlapping address space. The primary differences between VRs and VRFs are:
• For each routing protocol added to a VRF, only one process is started in the user VR and VRF. The
VRF protocol operates as one instance of the parent VR protocol, and additional child VRFs operate
as additional instances of the same parent VR protocol process. VRFs allow a protocol process
running in the parent VR to support many virtual router instances.
• ExtremeXOS supports up to 63 VRs and up to many more VRFs. (For the maximum number of
supported VRFs, see the ExtremeXOS Release Notes.)

In User Guide a lot of clear information about that.

User Guide you can download from here - http://www.extremenetworks.com/support/documentation

Or for older versions EXOS here - http://www.extremenetworks.com/support/documentation-archives

Thank you!

Thank you @AlexandrP. I am diving in User Documentation.
Userlevel 7
Hi Rahman,

Alexandr gave a great description of VRs in EXOS. You can also take a look at the following GTAC Knowledge article:
https://gtacknowledge.extremenetworks.com/articles/Q_A/What-is-a-Virtual-Router

-Brandon

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