Ask the Expert: Carrier Routing System (CRS) Hardware Architecture

[ciscomoderator]

With Vinay Kumar, Sudhir Kumar and Raj Pathak 

Welcome to the Cisco Support Community Ask the Expert conversation. This is an opportunity to learn and ask questions about Cisco Carrier Routing System (CRS) single-chassis and multichassis router hardware design and architecture with Cisco experts Vinay Kumar, Sudhir Kumar, and Raj Pathak. 

CRS routers are modular and distributed core routers developed by Cisco that enable service providers to deliver data, voice, and video services over a scalable IP next-generation network infrastructure. Today, CRS is one of the most trusted devices in the core of the service provider network and a proven architecture that has delivered 10 times the capacity over a period of 10 years.  Our three experts will cover the difference between CRS single-chassis and multichassis routers. They will also answer your questions about how CRS routers work and help in easily scaling the networks and different components of the CRS routers. 

For more details about CRS multichassis, read the blog and tech talk video. 

Hyperlink blog: https://supportforums.cisco.com/community/netpro/service-providers/ios-xr/blog/2013/11/06/community-tech-talk-crs-multichassis     

Vinay Kumar is an experienced support engineer with the High-Touch Technical Support Team, Bangalore, India. He has been supporting major service providers and large enterprise customers for routing, Multiprotocol Label Switching (MPLS), multicast, and Layer 2 VPN issues on all routing platforms. He has more than eight years of experience with service providers and has been in his current role from more than three years. Vinay has completed his CCIE routing and switching certification (CCIE no. 35210) and is a Cisco IOS XR Software specialist.

Sudhir Kumar is a customer support engineer in High-Touch Technical Services at Cisco specializing in service provider technologies and platforms. He serves as a support engineer for technical issues supporting Cisco IOS XR Software customers on Cisco CRS and Cisco XR 12000 Series Routers. Sudhir has more than eight years of experience in the IT industry and holds CCIE certification no. 35219 in routing and switching. 

Raj Pathak is a customer support engineer in High-Touch Technical Services at Cisco in Bangalore, India. He supports service provider customers for technical issues with Cisco IOS XR Software on Cisco CRS and Cisco XR 12000 Series Routers. He covers many technologies, including routing protocols, service provider, CRS, and Cisco IOS XR Software. He has more than seven years of experience in the IT industry and holds CCIE certification no. 38760 in routing and switching. 

Remember to use the rating system to let Vinay, Sudhir, and Raj know if you have received an adequate response.

Because of the volume expected during this event, our experts might not be able to answer every question. Remember that you can continue the conversation in the Service Providers community, subcommunity XR OS and Platforms shortly after the event. This event lasts through November 29, 2013. Visit this forum often to view responses to your questions and the questions of other Cisco Support Community members.

[Gustavo Hernandez]

Hello experts,

Is it mandatory to copy XR image on every RP in multi chassis setup ? Appreciate your help on this.

Thank you,

Lisa

[vinayk3]

Hi Lisa ,

You need to use the 'install add', 'install activate', and 'install commit'  so upgarde procedure remains the same.

Inastall add will add packages  to the disk of all RPs and shelf-controllers and install activate will  change the  code on RPs  and SCs and Finally Install Commit will check the consistency.

Thanks

Vinay, Sudhir,Raj

[Gustavo Hernandez]

Thank you for the quick answer!  One more question please - what is the main difference between MSC and FP40 card? 

Lisa

[Sudhir Kumar]

Hi Lisa,

I have already answered this question before in this event ,

let me explain again for you..

The MSC-B (Multi Service Card Rev B) is a cost reduced version of the  existing CRS-MSC(=) linecard which provides L3 functions for the  CRS-1router. 

CRS-MSC-B(=) will support ALL features that are  supported on the existing CRS-MSC(=).  No new software features have  been added.  There are NO new CLI, MIB or XML, all existing CLI, MIB and  XML on MSC will continue to be supported on MSC-B. 

CRS-MSC-B(=)  will NOT be supported with IOS XR release 3.5.x or earlier, but, it  will be able to co-exist with CRS-MSC so long as IOS XR Software is R3.6  and above.  CRS-MSC-B(=) is supported with release 3.6.0 (and upwards).

Also please note CRS MSC is end of sale now.

MSC cards provide better performance  than FP cards. Also for some Features FP cards need licence however for  MSC cards you dont need that.

Thanks

Sudhir,Vinay,Raj.

[Jackson Braddock · Accepted solution]

Hello gentlemen,

How many line card chassis can we connect with one fabric chassis?  Please advise.

Thank you.

Jackson

[dpothier]

hi Jackson,

MultiChassis capacity is gated by the OIM hardware
Up to  3 CRS-16 LCCs, in single topology mode where 8 OIM's/SFC's are required
Up to 9 CRS-16 LCCs, in multi-module topology mode where 24 OIM's/SFC's are required

Currently the CRS-3 MC System can support up to 9 LCC's with one FCC (9+1) when using PRP's.

regards,

david

[vinayk3]

Thanks David for answering to Jackson's Question.

Here is some more information about the same. There are two ways to connect to the Fabric Chassis.

1. Horizontal Cabling or Single Topology

2. Vertical Cabling or Multimodule topology.

So If we use Horizontal cabling as David's Mentioned we would require 8 fabric cards in FCC and  One Fabric card in LCC will be connected to the 3 ports on Fabric card in FCC . Each S2 card in FCC has 9 ports and Fabric card in LCC has 3 ports. So With Each Fabric card in Fabric card chassis we can connect One Fabric card from 3 Line card Chassis. In this case One Card in FCC will make one Fabric Plane so Each Card will represent one Seprate Plane so with Horizontal cabling we can connect up to 3 CRS chassis with one Fabric card chassis.

On ther other hand if we use Vertical Cabling we put 3 Fabric card in FCC in one plane and One card in FCC will connect to these three cards in one plane so we can scale better, we get redudancy for fabric cards and this way we can connect 9 CRS LCC to one FCC.

For more details about this please refer to our presentation.

https://supportforums.cisco.com/docs/DOC-37821

and Blog

https://supportforums.cisco.com/community/netpro/service-providers/ios-xr/blog/2013/11/06/community-tech-talk-crs-multichassis

Thanks

Vinay,sudhir,Raj

[dpothier]

hi Jackson,

I need to make a correction. While we have tested 9+1 MC internally the "official" supported number of LCC's stands at 8, at the moment. That would be an 8+1 MC, or 8 LCC's + 1 FCC. And we do have customers using the 8+1 MC system today.

regards,

david

[Jackson Braddock]

Appreciate your response David, Vinay, Sudhir and Raj.  One more thing.  I'm also curious as to how it will be decided which rack will become Rack 0 and Rack 1 in CRS multi chassis setup? 

Jackson

[Nicolas Fevrier]

Hi Jackson,

it will be done by configuration in admin mode based on the serial number of your line cards and fabric cards chassis:

dsc serial TBMwwwwwwww rack 0

dsc serial TBAxxxxxxxxx rack 1

dsc serial TBAyyyyyyyy rack 2

dsc serial TBAzzzzzzz rack 240

Cheers,

N.

[vinayk3]

Hi Jackson ,

Nicols is right you need to define the serinal number of the chassis with the Rack number.

You can also refer to the following presentation.

https://supportforums.cisco.com/docs/DOC-37821

Thanks

Vinay, Sudhir,Raj