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New Member

Multicast capacity planning

Hi,

When we  select the routers for Multicast , what are all the thing need to consider ?

For example : Number of streams supported , number groups supported , Bandwidth capacity for multicast etc ? Can some one please help me to point out the question need to ask while selecting the router for multicast ?

In our desing Multicast is tunnelled through GRE and Shared tree only be used using static RP. So selecting RP is a big process i guess. Also what are all the things need to consider for slecting the hardware spec for RP as well. Please help !!

Thanks in advance,

Cheers,

A

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Accepted Solutions
Super Bronze

Multicast capacity planning

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

This is the type of questions you may need to discuss with Cisco technical sales reps assuming you know exactly what you want to do with you multicast stream(s).

Whatever you select, you might also want some product guarantees that if performance doesn't meet you specifications you can return equipment or a try before you buy option.

Trouble with multicast - it doesn't get utilized like unicast, so actual performance is much more of an unknown.  (For example, you don't typically see multicast performance stats on data sheets.)

Super Bronze

Multicast capacity planning

Disclaimer

The   Author of this posting offers the information contained within this   posting without consideration and with the reader's understanding that   there's no implied or expressed suitability or fitness for any purpose.   Information provided is for informational purposes only and should not   be construed as rendering professional advice of any kind. Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In   no event shall Author be liable for any damages whatsoever (including,   without limitation, damages for loss of use, data or profit) arising  out  of the use or inability to use the posting's information even if  Author  has been advised of the possibility of such damage.

Posting

As far as QoS is concerned, not much difference between unicast vs. multicast.  If both are IP packets, both have ToS bytes.

Excluding really old IOSs, GRE tunnels should copy the IP ToS value.  Pre-classify is needed if, on the physical interface, you want to look at other GRE IP header info.  It's not needed if just using ToS.  Also it (pre-classify) will only work on the device sourcing the GRE tunnel.

I haven't done QoS with native MPLS, but if you're working with a MPLS vendor providing L3 VPN, you just set ToS to work with whatever QoS model they support (vendor might have various options).

5 REPLIES
Super Bronze

Multicast capacity planning

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

This is the type of questions you may need to discuss with Cisco technical sales reps assuming you know exactly what you want to do with you multicast stream(s).

Whatever you select, you might also want some product guarantees that if performance doesn't meet you specifications you can return equipment or a try before you buy option.

Trouble with multicast - it doesn't get utilized like unicast, so actual performance is much more of an unknown.  (For example, you don't typically see multicast performance stats on data sheets.)

New Member

Multicast capacity planning

Thanks for the info.

Also i am searching . how to configure end to end  QOS for multicast within the GRE . I know this can be done by pre-classify in tunnel and set policy-map in physical interface. But inorder to provide QOS for the PE and P routers , the CPE need to set IPP/DSCP and then PE can use  EXP bit accordingkly to provide end to end QOS.

But for how to set DSCP/IPP value in a way that multicast/GRE traffic can get end to end QOS ?

Help !!!!

Thanks in advance,

Anil.

Super Bronze

Multicast capacity planning

Disclaimer

The   Author of this posting offers the information contained within this   posting without consideration and with the reader's understanding that   there's no implied or expressed suitability or fitness for any purpose.   Information provided is for informational purposes only and should not   be construed as rendering professional advice of any kind. Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In   no event shall Author be liable for any damages whatsoever (including,   without limitation, damages for loss of use, data or profit) arising  out  of the use or inability to use the posting's information even if  Author  has been advised of the possibility of such damage.

Posting

As far as QoS is concerned, not much difference between unicast vs. multicast.  If both are IP packets, both have ToS bytes.

Excluding really old IOSs, GRE tunnels should copy the IP ToS value.  Pre-classify is needed if, on the physical interface, you want to look at other GRE IP header info.  It's not needed if just using ToS.  Also it (pre-classify) will only work on the device sourcing the GRE tunnel.

I haven't done QoS with native MPLS, but if you're working with a MPLS vendor providing L3 VPN, you just set ToS to work with whatever QoS model they support (vendor might have various options).

New Member

Multicast capacity planning

Can provide BW reservation for this on the CPE, also need to set IPP value so that the PEs can use corresponding EXP bit to provide end to end QOS for that traffic, but how can i set IPP bit for multicast traffic within GRE ?

Setting IPP by matching protocol GRE (or matching GRE termination points) is enough ? and the PEs can use EXP bit accordingly for end to end QOS ? Not sure method will provide proper QOS for Multicast traffic which is tunnelling through GRE and transparent within the core ?

Super Bronze

Multicast capacity planning

Disclaimer

The   Author of this posting offers the information contained within this   posting without consideration and with the reader's understanding that   there's no implied or expressed suitability or fitness for any purpose.   Information provided is for informational purposes only and should not   be construed as rendering professional advice of any kind. Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In   no event shall Author be liable for any damages whatsoever (including,   without limitation, damages for loss of use, data or profit) arising  out  of the use or inability to use the posting's information even if  Author  has been advised of the possibility of such damage.

Posting

You would set ToS on the multicast packet before it enters the GRE tunnel.

You should be able to set ToS on the GRE packet, but how would you know what GRE packets contains?  (Pre-classify might support this.)

Unless you're doing MPLS end-to-end, EXP would not be useful for end-to-end QoS unless you overwrite original ToS upon MPLS egress in "uniform mode".

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