ASR9922 QOS VQI & VOQ

[mufaddal.presswala]

Hello All,

I am trying to understand the difference between the usage of VQI and VOQs and exactly in which stage what is used. Also it would be good if someone can clarify the mapping between them.

The question comes after going through the Cisco Live presentation (BRKSPG-2904) as one presentation (2014 Melbourne) says 1 VOQ is divided into 4 VQI based on traffic classes while the other presentation(2014 San Francisco) says 1 VQI is equivalent to 4 VOQs (for typhoon LCs). The arbiter ASIC does it grant a VOQ or a VQI credit ? Also one mentions the traffic is load balanced internally based on VQI while the other mentions VOQs.

P.S: The cisco live presentation and video sessions helped me immensely to understand the other bits and pieces of the ASR9K architecture. 

Thanks,

Muffadal

[xthuijs · Accepted solution]

Hi Muffadal,

thanks for letting me know the use that the preso provides!! The original versions created are generally presented on CL in the US. The authentic presentations for ID 2904 are from Orlando 2013 and Sanfran 2014, the content from them is much different as I never try to run the same show twice. This year will be different once again :)

Other locations take the presentations, but might change the content, just so you know.

To answer your question directly, the terms VOQ and VQI (virtual output queue vs index) are sometimes used interchangeably, and that is ok.

The VOQ is a queue (SET) that represents a 10G entity in the system. (10G is somewhat of a misnomer also since the actual queue set is shaped at I think 17G now in the latest releases).

Each queue set has 4 different priorities. P1, P2, BE and mcast. They are generally referenced as VQI.

Some show commands also use it interchangeably.

If you take the sanfran 2014 preso there is some good detail that can extrapolate how to monitor the VQI's (yup individual queues) on a per 10G entity bases and we're also enhancing the commands to make them easier to understand and use, probably somewhere 532 timeframe (give or take:)

cheers

xander

[mufaddal.presswala]

Thank you Xander. 

It definitely helps me clearing a lot of confusion around VQI and VOQs. 

I will look into the commands for monitoring the VQI in the SanFran 2014 preso as we are planning to deploy the tomahawk hardware.

[adfsdafs adsfafds]

Hi Xander,

Has VOQ/VQI changed in Tomahawk as ports go beyond 10G? 

2016/usa/pdf/BRKARC-2003 page 72
Virtual Queue Identifier (VQI)
• Each Physical Interface is Identified by VQI. VQI is used to load balance traffic across fabric
• One VQI Comprise 4 VOQ – Priority 1, 2, 3 and Normal
• On 8x100G&4x100G Tomahawk LCs:
• 12 VQI each physical interface(9922, 9912, 9910, 9904)
• On 12x100G Tomahawk LCs:
• MIX mode: 12 VQI each physical interface(9922, 9912, 9910, 9904)
• High Bandwidth Mode: 6 VQI each physical interface(9922, 9912, 9910)
• On Typhoon LCs, NP is designed for multiple 10G, 40G, and 100G ports.
• Each 10G port is 1:1 mapped to one VQI
• Each 40G port is mapped to 8 VQI
• Each 100G port is mapped to 16 VQI 

16 VOQ for 100GE port sounds quite confusing. Does it actually mean 16x6.25Gbps links to make up the SerDes?

[Aleksandar Vidakovic]

On Tomahawk line cards a 100G interaface is represented by a single VQI. Now, because you can use any 100G port on Tomahawk as 10x10G breakout, we reserve 96 VQIs per 8x100G Tomahawk line card. That way you can dynamically change the mode from full 100G to 10x10G.

[federico.luzzi]

Hi Xander

We are working with a client that needs to decide their strategy for the future in their ASR9922 We need to know how many VQIs are used by Tomahawk LCs that are not A99, this is the list:

• A9K-8X100G-LB-SE
• A9K-8X100G-LB-TR
• A9K-8X100GE-SE
• A9K-8X100GE-TR
• A9K-4X100GE-SE
• A9K-4X100GE-TR
• A9K-400G-DWDM-TR
• A9K-MOD400-SE
• A9K-MOD400-TR
• A9K-MOD200-SE
• A9K-MOD200-TR
• A9K-24X10GE-1G-SE
• A9K-24X10GE-1G-TR
• A9K-48X10GE-1G-SE
• A9K-48X10GE-1G-TR

Thanks!!

[mivens]

The VQI assignments per card changed in XR 6.1.3.

Output below is taken from XR 6.1.4:

RP/0/RP0/CPU0:asr9922#sh controllers fabric vqi assignment requirement
Current mode: Interop mode - 1K VQIsCardType        Mode
                Interop   Highbandwidth A99-Highbandwidth
---------------------------------------------------------
A9K-24x10G*       24         Unsupported    Unsupported
A9K-2x100G*       16         Unsupported    Unsupported
A9K-MOD160*       24         Unsupported    Unsupported
A9K-MOD80*        16         Unsupported    Unsupported
A9K-36x10G*       40         Unsupported    Unsupported
A9K-VSM*          16         Unsupported    Unsupported
A9*-40G*          8          Unsupported    Unsupported
A9*-4T16G*        8          Unsupported    Unsupported
A9*-8x100G*       80         80             80
A9*-4x100G*       48         48             48
A9*-MOD200*       24         24             24
A9*-MOD400*       40         40             40
A9*-48x10G*       80         80             80
A9*-12x100G*      96         48             48
A9*-400G*         40         40             40
A9*-24X10GE-1G*   24         24             24
A9*-48X10GE-1G*   48         48             48

[federico.luzzi]

Thanks! That's very useful information, just one more thing, the client is running now 6.0.2, is it possible to get this same information for that version or any other previous 6.1.3?

thank you again!

[mivens]

Unfortunately, that command was only introduced in XR 6.1 so can't be used on a router running 6.0.

From some old notes, for XR releases between 5.3.0 and 6.1.2, 100GE ports are allocated 12 VQIs, so the 8x100GE LCs use 96, the 2x100GEs consume 24 and the 4x100GEs use 48.

[Anuj Singhi]

@xthuijs can you please provide those links of cisco live 2013 and 2014 for TR and SE LC difference?

[xr-escalation]

Search for BRKSPG-2904 Cisco Live 2014

/Aleksandar

[xthuijs]

Here are a good set of references,
also the sanfran 2014 and Orlando 2013 are good ones to have
https://ciscolive.cisco.com/on-demand-library/?search.event=ciscoliveus2018&search.event=ciscoliveus2017&search.event=ciscoliveus2015&search=2904#/
xander