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ISL on VSX

Hi friends.
Is there any restriction about the number of member links of the ISL in a VSX deployment? ... I will use 40GE ports for ISL.
Regards

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Re: ISL on VSX

ISL has only one link, that is either a physical link or a LAG.

Then up to 8 links can configured part of the LAG.

Consequently up to 8 physical links can support ISL communication.

8x10 or 8x40 or 8x100.

Occasional Contributor I

Re: ISL on VSX

 

Re: ISL on VSX

The rule of thumb for ISL BW is to plan enough BW for a filure scenario

like supporting the uplink load over the ISL in case one of the uplink fails (this is one example among others). If you plan 1x40G uplink per VSX node to connect upstream, I would recommend to use 2x40G for ISL.

ISL protocol as such won't consumme a lot of BW.

Re: ISL on VSX

Hi Vicent.

I have search de VSX configuration guide for the Aruba 8400 and have not found anything about ISL physical member links limit.

 

The only restiction I have found is about the VSX LAG:

"A VSX LAG supports a maximum of four member links per switch segment. A VSX LAG across a downstream switch can have at most a total of eight member links"

 

But it seems this talks about LAG between 2 core switches in VSX and a Distribution/Access Switch.

 

Regards

 


PS: If you feel this information is useful and solved your question or problem, please do not forget to mark it as a solution and give me some kudos.

Re: ISL on VSX

Please refer to p10 of LAG config guide that mentions a LAG can have up to eight physical interfaces.

Please note that to create ISL connectivity you use one regular LAG,

that can have up to 8 ports.

The limit of 4 you mentioned is the number of physical ports you can assign on VSX primary and on VSX secondary, for a total of 8, in a VSX LAG.

MVP Expert

Re: ISL on VSX

As @vincent.giles mentioned above, since the VSX ISL can be deployed also using a LAG approach (so the resulting LAG is just a classic non Multi-Chassis LAG just a little bit special due its VSX ISL assigned role) then classic LAG's restrictions/requirements will apply...those ones include a maximum of 8 member interfaces for each LAG (and, I add, the maximum LAG Id number that can be assigned will be 128, IIRC <- there is a non written best practice that suggest to deploy the VSX ISL as LAG using the Id 128...but this detail is just beyond your initial question).

Highlighted

Re: ISL on VSX

Thank you Vincent and Parnassus.

Pretty clear.

As you already said, creating an ISL makes reference to an LAG group, so, the limit is imposed by the capacity of the LAG group, in this case: 8 physical links per LAG group, as the LAG configuration guide says.

 

Here you can see an example of configuration so that anybody could understand what Vincent and Parnassus talk about:

---------------------------------------------

! LAG for Inter-Switch-Link
  interface lag 128
    no shutdown
    no routing
    lacp mode active
    vlan trunk native 10 tag
    vlan trunk allowed 10,20
  interface 1/1/2
    no shutdown
    mtu 2068
    lag 128
  interface 1/1/3
    no shutdown
    mtu 2068
    lag 128
    exit

! Inter-Switch-Link setting
  vsx
    inter-switch-link lag 128
    keepalive peer 1.1.2.2 source 1.1.2.1

---------------------------------------------------------

Steps:

  • Create a LAG (LAG 128 in the example above)
  • Assign member ports to the LAG (interface 1/1/2 and interface 1/1/3)
  • Finally, tell the VSX that the ISL will use LAG 128.

Regards

 

 


PS: If you feel this information is useful and solved your question or problem, please do not forget to mark it as a solution and give me some kudos.
MVP Expert

Re: ISL on VSX

Mine VSX ISL configuration actually is this one:

 

interface lag 128
    vsx-sync vlans
    description VSX-ISL-LAG128-Link
    no shutdown
    no routing
    vlan trunk native 1 tag
    vlan trunk allowed all
    lacp mode active

VSX ISL Member Interfaces in my case are 4x40Gbps:

 

interface 1/1/49 
    description 8320-1-VSX-ISL-1-1-49
    no shutdown
    mtu 9198
    lag 128
interface 1/1/50 
    description 8320-1-VSX-ISL-1-1-50
    no shutdown
    mtu 9198
    lag 128
interface 1/1/52 
    description 8320-1-VSX-ISL-1-1-52
    no shutdown
    mtu 9198
    lag 128
interface 1/1/53 
    description 8320-1-VSX-ISL-1-1-53
    no shutdown
    mtu 9198
    lag 128

VSX configuration includes:

 

vsx
    inter-switch-link lag 128
    role primary
    keepalive peer 10.250.250.2 source 10.250.250.1 vrf VSX-ISL-Keepalive
    linkup-delay-timer 35

As you can see I lowered the default linkup-delay-timer to 35 seconds (pretty enough on my environment) and my dedicated VRF for VSX ISL Keepalive is called "VSX-ISL-Keepalive".

 

VSX Keepalive interface (actually just a single link) is:

 

interface 1/1/48 
    description ISL-Keepalive
    no shutdown
    vrf attach VSX-ISL-Keepalive
    ip address 10.250.250.1/30

even if I plan to use a 2 ports LAG.

Re: ISL on VSX

Hi Parnassus,

Thanks for sharing your configuration with us, it has more details than mine and it will be very helpful.
Pals, finally the idea is the same, just with more details and suggestions from Parnassus.

Parnassus,

I would like to harden the keepalive link using a LAG group with 2 physical ports (using your configuration example), this would be my configuration for the primary vsx member, would you mind suggesting me any other add?:


interface lag 10
description ISL-Keepalive
no shutdown
vrf attach VSX-ISL-Keepalive
ip address 10.250.250.1/30
lacp mode active

interface 1/1/1
description 8320-1-ISL-Keepalive-1-1-1
no shutdown
mtu 9198
lag 10

interface 1/1/48
description 8320-1-ISL-Keepalive-1-1-48
no shutdown
mtu 9198
lag 10

vsx
inter-switch-link lag 128
role primary
keepalive peer 10.250.250.2 source 10.250.250.1 vrf VSX-ISL-Keepalive
linkup-delay-timer 35

Have a nice day pals

PS: If you feel this information is useful and solved your question or problem, please do not forget to mark it as a solution and give me some kudos.
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