Re: [c-nsp] Multicast replication over GRE on 7600s

2010-09-28 Thread Tim Stevenson 
I'm gonna have to admit I'm getting rusty on some of these details, 
but IIRC, for standard GRE OIF, it is ingress replicated and 
recirculated to do a lookup on the outer IP header; but other 
non-tunnel OIFs can still be egress replicated. For MVPN 
configurations, the entire box is forced to ingress mode.


Hope that helps,
Tim


At 10:34 AM 9/28/2010, Ben Lovell (belovell) declared:

Tim,

Just to make sure I am understanding. For a certain group, 
non-tunnel OIFs would still use egress replication and only tunnel 
OIFs would be ingress or the whole group falls back to ingress?


-Ben


~
  ..  Benjamin Lovell
  ||  AS Video Practice
 |||  ||| Cisco Customer Advocacy
   .|.  .|.   Research Triangle Park, NC
.:|:..:|:.Email: 
belov...@cisco.com

 ciscodesk:919.392.8255 cell:203.509.1562
~

On Sep 28, 2010, at 1:13 PM, Tim Stevenson wrote:

With a tunnel you don't know which is the egress card until the 
encap is done. That's why tunnel OIFs are always ingress replicated.


Tim

At 09:43 AM 9/28/2010, Ben Lovell (belovell) declared:

You would not have to force the box back to ingress. These packet 
would take the ingress forwarding path instead of egress. Other 
groups would still function in egress.


I agree. it's hard to see how this would work in egress as the 
idea of replication is all packets are getting the same rewrite(on 
ingress) and egress card just needs to make copies.  I suppose you 
could replicate in the normal fashion to each egress LC plus one 
more copy for the GRE tunnel would would then loop through lookup 
process again for GRE encap but this is purely conjecture on my part.


-Ben



~
 ..  Benjamin Lovell
 ||  AS Video Practice
|||  ||| Cisco Customer Advocacy
  .|.  .|.   Research Triangle Park, NC
   .:|:..:|:.Email: 
belov...@cisco.com

ciscodesk:919.392.8255 cell:203.509.1562
~

On Sep 28, 2010, at 12:34 PM, John Neiberger wrote:

> Now that I think about it, I bet that egress mode isn't allowed in
> this scenario. It would make sense that only ingress mode would work,
> that way the ingress Janus/Metro would take care of replicating out to
> all the receivers, including the GRE tunnel. I'm having trouble
> visualizing how that would work in egress mode.
>
> It was worth checking into, though. We have a situation where this
> might be useful temporarily. But since we're running egress on our
> 7600s, moving back to ingress is just not an option.
>
> Once again, thanks for your help!
> John
>
> On Tue, Sep 28, 2010 at 10:25 AM, Benjamin Lovell 
<belov...@cisco.com> wrote:
>> The same hardware(janus/metro) is responsible for the 
replication(no punt to
>> CPU) but due to the GRE ecanp required the packet will have to 
go through a
>> longer forwarding process(more lookups) and performance will 
be reduced. I
>> don't have any solid numbers but my guess is that forwarding 
rate would be

>> approx 1/2.
>> The part I am not sure about is if egress replication is still 
possible. In

>> the mVPN scenario only ingress replication is possible due to the GRE
>> encap/decap but I am not sure if this same limitation applies to P2P GRE
>> tunnels. Let me know if this piece would be important to you 
and I can look

>> into it.
>> The one caveat to be careful of here(applies to unicast as well) is that
>> each GRE tunnel must be sourced from a unique IP address on 
the box. Using
>> the same source IP on more than one GRE tunnel will cause all 
traffic in GRE

>> decap path to be punted to CPU and maybe multicast on encap path in some
>> scenarios.
>> -Ben
>>
>>
>> ~
>>   ..  Benjamin Lovell
>>   ||  AS Video Practice
>>  |||  ||| Cisco Customer Advocacy
>>.|.  .|.   Research Triangle Park, NC
>> .:|:..:|:.Email: 
belov...@cisco.com

>>  ciscodesk:919.392.8255 cell:203.509.1562
>> ~
>> On Sep 28, 2010, at 10:02 AM, John Neiberger wrote:
>>
>> I have an architectural question. As an example, let's say you have
>> two 7600s directly connected via routed links running PIM and you have
>> primarily multicast traffic. If you're running egress replication
>> mode, you either have a Janus ASIC or Metropolis ASIC responsibl

Re: [c-nsp] Multicast replication over GRE on 7600s

2010-09-28 Thread Benjamin Lovell 
Tim,

Just to make sure I am understanding. For a certain group, non-tunnel OIFs 
would still use egress replication and only tunnel OIFs would be ingress or the 
whole group falls back to ingress?

-Ben


~
  ..  Benjamin Lovell
  ||  AS Video Practice
 |||  ||| Cisco Customer Advocacy
   .|.  .|.   Research Triangle Park, NC
.:|:..:|:.Email:  belov...@cisco.com
 ciscodesk:919.392.8255 cell:203.509.1562
~

On Sep 28, 2010, at 1:13 PM, Tim Stevenson wrote:

> With a tunnel you don't know which is the egress card until the encap is 
> done. That's why tunnel OIFs are always ingress replicated.
> 
> Tim
> 
> At 09:43 AM 9/28/2010, Ben Lovell (belovell) declared:
> 
>> You would not have to force the box back to ingress. These packet would take 
>> the ingress forwarding path instead of egress. Other groups would still 
>> function in egress.
>> 
>> I agree. it's hard to see how this would work in egress as the idea of 
>> replication is all packets are getting the same rewrite(on ingress) and 
>> egress card just needs to make copies.  I suppose you could replicate in the 
>> normal fashion to each egress LC plus one more copy for the GRE tunnel would 
>> would then loop through lookup process again for GRE encap but this is 
>> purely conjecture on my part.
>> 
>> -Ben
>> 
>> 
>> 
>> ~
>>  ..  Benjamin Lovell
>>  ||  AS Video Practice
>> |||  ||| Cisco Customer Advocacy
>>   .|.  .|.   Research Triangle Park, NC
>>.:|:..:|:.Email:  belov...@cisco.com
>> ciscodesk:919.392.8255 cell:203.509.1562
>> ~
>> 
>> On Sep 28, 2010, at 12:34 PM, John Neiberger wrote:
>> 
>> > Now that I think about it, I bet that egress mode isn't allowed in
>> > this scenario. It would make sense that only ingress mode would work,
>> > that way the ingress Janus/Metro would take care of replicating out to
>> > all the receivers, including the GRE tunnel. I'm having trouble
>> > visualizing how that would work in egress mode.
>> >
>> > It was worth checking into, though. We have a situation where this
>> > might be useful temporarily. But since we're running egress on our
>> > 7600s, moving back to ingress is just not an option.
>> >
>> > Once again, thanks for your help!
>> > John
>> >
>> > On Tue, Sep 28, 2010 at 10:25 AM, Benjamin Lovell  
>> > wrote:
>> >> The same hardware(janus/metro) is responsible for the replication(no punt 
>> >> to
>> >> CPU) but due to the GRE ecanp required the packet will have to go through 
>> >> a
>> >> longer forwarding process(more lookups) and performance will be reduced. I
>> >> don't have any solid numbers but my guess is that forwarding rate would be
>> >> approx 1/2.
>> >> The part I am not sure about is if egress replication is still possible. 
>> >> In
>> >> the mVPN scenario only ingress replication is possible due to the GRE
>> >> encap/decap but I am not sure if this same limitation applies to P2P GRE
>> >> tunnels. Let me know if this piece would be important to you and I can 
>> >> look
>> >> into it.
>> >> The one caveat to be careful of here(applies to unicast as well) is that
>> >> each GRE tunnel must be sourced from a unique IP address on the box. Using
>> >> the same source IP on more than one GRE tunnel will cause all traffic in 
>> >> GRE
>> >> decap path to be punted to CPU and maybe multicast on encap path in some
>> >> scenarios.
>> >> -Ben
>> >>
>> >>
>> >> ~
>> >>   ..  Benjamin Lovell
>> >>   ||  AS Video Practice
>> >>  |||  ||| Cisco Customer Advocacy
>> >>.|.  .|.   Research Triangle Park, NC
>> >> .:|:..:|:.Email:  belov...@cisco.com
>> >>  ciscodesk:919.392.8255 cell:203.509.1562
>> >> ~
>> >> On Sep 28, 2010, at 10:02 AM, John Neiberger wrote:
>> >>
>> >> I have an architectural question. As an example, let's say you have
>> >> two 7600s directly connected via routed links running PIM and you have
>> >> primarily multicast traffic. If you're running egress replication
>> >> mode, you either have a Janus ASIC or Metropolis ASIC responsible for
>> >> the multicast replication, which happens on the line card. But how
>> >> would things change if you were not running multicast directly on the
>> >> routed link, but instead used a GRE tunnel between the two routers?
>> >>
>> >> I guess I have a couple of

Re: [c-nsp] Multicast replication over GRE on 7600s

2010-09-28 Thread Tim Stevenson 
With a tunnel you don't know which is the egress card until the encap 
is done. That's why tunnel OIFs are always ingress replicated.


Tim

At 09:43 AM 9/28/2010, Ben Lovell (belovell) declared:

You would not have to force the box back to ingress. These packet 
would take the ingress forwarding path instead of egress. Other 
groups would still function in egress.


I agree. it's hard to see how this would work in egress as the idea 
of replication is all packets are getting the same rewrite(on 
ingress) and egress card just needs to make copies.  I suppose you 
could replicate in the normal fashion to each egress LC plus one 
more copy for the GRE tunnel would would then loop through lookup 
process again for GRE encap but this is purely conjecture on my part.


-Ben



~
  ..  Benjamin Lovell
  ||  AS Video Practice
 |||  ||| Cisco Customer Advocacy
   .|.  .|.   Research Triangle Park, NC
.:|:..:|:.Email:  belov...@cisco.com
 ciscodesk:919.392.8255 cell:203.509.1562
~

On Sep 28, 2010, at 12:34 PM, John Neiberger wrote:

> Now that I think about it, I bet that egress mode isn't allowed in
> this scenario. It would make sense that only ingress mode would work,
> that way the ingress Janus/Metro would take care of replicating out to
> all the receivers, including the GRE tunnel. I'm having trouble
> visualizing how that would work in egress mode.
>
> It was worth checking into, though. We have a situation where this
> might be useful temporarily. But since we're running egress on our
> 7600s, moving back to ingress is just not an option.
>
> Once again, thanks for your help!
> John
>
> On Tue, Sep 28, 2010 at 10:25 AM, Benjamin Lovell 
 wrote:
>> The same hardware(janus/metro) is responsible for the 
replication(no punt to
>> CPU) but due to the GRE ecanp required the packet will have to 
go through a

>> longer forwarding process(more lookups) and performance will be reduced. I
>> don't have any solid numbers but my guess is that forwarding rate would be
>> approx 1/2.
>> The part I am not sure about is if egress replication is still 
possible. In

>> the mVPN scenario only ingress replication is possible due to the GRE
>> encap/decap but I am not sure if this same limitation applies to P2P GRE
>> tunnels. Let me know if this piece would be important to you and 
I can look

>> into it.
>> The one caveat to be careful of here(applies to unicast as well) is that
>> each GRE tunnel must be sourced from a unique IP address on the box. Using
>> the same source IP on more than one GRE tunnel will cause all 
traffic in GRE

>> decap path to be punted to CPU and maybe multicast on encap path in some
>> scenarios.
>> -Ben
>>
>>
>> ~
>>   ..  Benjamin Lovell
>>   ||  AS Video Practice
>>  |||  ||| Cisco Customer Advocacy
>>.|.  .|.   Research Triangle Park, NC
>> .:|:..:|:.Email:  belov...@cisco.com
>>  ciscodesk:919.392.8255 cell:203.509.1562
>> ~
>> On Sep 28, 2010, at 10:02 AM, John Neiberger wrote:
>>
>> I have an architectural question. As an example, let's say you have
>> two 7600s directly connected via routed links running PIM and you have
>> primarily multicast traffic. If you're running egress replication
>> mode, you either have a Janus ASIC or Metropolis ASIC responsible for
>> the multicast replication, which happens on the line card. But how
>> would things change if you were not running multicast directly on the
>> routed link, but instead used a GRE tunnel between the two routers?
>>
>> I guess I have a couple of questions:
>>
>> 1. How is GRE traffic processed in this scenario? Can it be forwarded
>> at high rates on the line card or is it punted to the CPU?
>>
>> 2. Which hardware is responsible for multicast replication over 
GRE tunnels?

>>
>> Any ideas?
>>
>>
>> Thanks!
>> John
>> ___
>> cisco-nsp mailing list  cisco-nsp@puck.nether.net
>> 
https://puck.nether.net/mailman/listinfo/cisco-nsp
>> archive at 
http://puck.nether.net/pipermail/cisco-nsp/

>>
>>

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Tim Stevenson, tstev...@cisco.com
Routing & Switching CCIE #5561
Distinguished Tech

Re: [c-nsp] Multicast replication over GRE on 7600s

2010-09-28 Thread Benjamin Lovell 
You would not have to force the box back to ingress. These packet would take 
the ingress forwarding path instead of egress. Other groups would still 
function in egress. 

I agree. it's hard to see how this would work in egress as the idea of 
replication is all packets are getting the same rewrite(on ingress) and egress 
card just needs to make copies.  I suppose you could replicate in the normal 
fashion to each egress LC plus one more copy for the GRE tunnel would would 
then loop through lookup process again for GRE encap but this is purely 
conjecture on my part.

-Ben



~
  ..  Benjamin Lovell
  ||  AS Video Practice
 |||  ||| Cisco Customer Advocacy
   .|.  .|.   Research Triangle Park, NC
.:|:..:|:.Email:  belov...@cisco.com
 ciscodesk:919.392.8255 cell:203.509.1562
~

On Sep 28, 2010, at 12:34 PM, John Neiberger wrote:

> Now that I think about it, I bet that egress mode isn't allowed in
> this scenario. It would make sense that only ingress mode would work,
> that way the ingress Janus/Metro would take care of replicating out to
> all the receivers, including the GRE tunnel. I'm having trouble
> visualizing how that would work in egress mode.
> 
> It was worth checking into, though. We have a situation where this
> might be useful temporarily. But since we're running egress on our
> 7600s, moving back to ingress is just not an option.
> 
> Once again, thanks for your help!
> John
> 
> On Tue, Sep 28, 2010 at 10:25 AM, Benjamin Lovell  wrote:
>> The same hardware(janus/metro) is responsible for the replication(no punt to
>> CPU) but due to the GRE ecanp required the packet will have to go through a
>> longer forwarding process(more lookups) and performance will be reduced. I
>> don't have any solid numbers but my guess is that forwarding rate would be
>> approx 1/2.
>> The part I am not sure about is if egress replication is still possible. In
>> the mVPN scenario only ingress replication is possible due to the GRE
>> encap/decap but I am not sure if this same limitation applies to P2P GRE
>> tunnels. Let me know if this piece would be important to you and I can look
>> into it.
>> The one caveat to be careful of here(applies to unicast as well) is that
>> each GRE tunnel must be sourced from a unique IP address on the box. Using
>> the same source IP on more than one GRE tunnel will cause all traffic in GRE
>> decap path to be punted to CPU and maybe multicast on encap path in some
>> scenarios.
>> -Ben
>> 
>> 
>> ~
>>   ..  Benjamin Lovell
>>   ||  AS Video Practice
>>  |||  ||| Cisco Customer Advocacy
>>.|.  .|.   Research Triangle Park, NC
>> .:|:..:|:.Email:  belov...@cisco.com
>>  ciscodesk:919.392.8255 cell:203.509.1562
>> ~
>> On Sep 28, 2010, at 10:02 AM, John Neiberger wrote:
>> 
>> I have an architectural question. As an example, let's say you have
>> two 7600s directly connected via routed links running PIM and you have
>> primarily multicast traffic. If you're running egress replication
>> mode, you either have a Janus ASIC or Metropolis ASIC responsible for
>> the multicast replication, which happens on the line card. But how
>> would things change if you were not running multicast directly on the
>> routed link, but instead used a GRE tunnel between the two routers?
>> 
>> I guess I have a couple of questions:
>> 
>> 1. How is GRE traffic processed in this scenario? Can it be forwarded
>> at high rates on the line card or is it punted to the CPU?
>> 
>> 2. Which hardware is responsible for multicast replication over GRE tunnels?
>> 
>> Any ideas?
>> 
>> 
>> Thanks!
>> John
>> ___
>> cisco-nsp mailing list  cisco-nsp@puck.nether.net
>> https://puck.nether.net/mailman/listinfo/cisco-nsp
>> archive at http://puck.nether.net/pipermail/cisco-nsp/
>> 
>> 

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Re: [c-nsp] Multicast replication over GRE on 7600s

2010-09-28 Thread John Neiberger 
Now that I think about it, I bet that egress mode isn't allowed in
this scenario. It would make sense that only ingress mode would work,
that way the ingress Janus/Metro would take care of replicating out to
all the receivers, including the GRE tunnel. I'm having trouble
visualizing how that would work in egress mode.

It was worth checking into, though. We have a situation where this
might be useful temporarily. But since we're running egress on our
7600s, moving back to ingress is just not an option.

Once again, thanks for your help!
John

On Tue, Sep 28, 2010 at 10:25 AM, Benjamin Lovell  wrote:
> The same hardware(janus/metro) is responsible for the replication(no punt to
> CPU) but due to the GRE ecanp required the packet will have to go through a
> longer forwarding process(more lookups) and performance will be reduced. I
> don't have any solid numbers but my guess is that forwarding rate would be
> approx 1/2.
> The part I am not sure about is if egress replication is still possible. In
> the mVPN scenario only ingress replication is possible due to the GRE
> encap/decap but I am not sure if this same limitation applies to P2P GRE
> tunnels. Let me know if this piece would be important to you and I can look
> into it.
> The one caveat to be careful of here(applies to unicast as well) is that
> each GRE tunnel must be sourced from a unique IP address on the box. Using
> the same source IP on more than one GRE tunnel will cause all traffic in GRE
> decap path to be punted to CPU and maybe multicast on encap path in some
> scenarios.
> -Ben
>
>
> ~
>           .            .          Benjamin Lovell
>           |            |          AS Video Practice
>          |||          |||         Cisco Customer Advocacy
>        .|.      .|.       Research Triangle Park, NC
>     .:|:..:|:.    Email:  belov...@cisco.com
>              cisco            desk:919.392.8255 cell:203.509.1562
> ~
> On Sep 28, 2010, at 10:02 AM, John Neiberger wrote:
>
> I have an architectural question. As an example, let's say you have
> two 7600s directly connected via routed links running PIM and you have
> primarily multicast traffic. If you're running egress replication
> mode, you either have a Janus ASIC or Metropolis ASIC responsible for
> the multicast replication, which happens on the line card. But how
> would things change if you were not running multicast directly on the
> routed link, but instead used a GRE tunnel between the two routers?
>
> I guess I have a couple of questions:
>
> 1. How is GRE traffic processed in this scenario? Can it be forwarded
> at high rates on the line card or is it punted to the CPU?
>
> 2. Which hardware is responsible for multicast replication over GRE tunnels?
>
> Any ideas?
>
>
> Thanks!
> John
> ___
> cisco-nsp mailing list  cisco-...@puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>
>

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Re: [c-nsp] Multicast replication over GRE on 7600s

2010-09-28 Thread Benjamin Lovell 
The same hardware(janus/metro) is responsible for the replication(no punt to 
CPU) but due to the GRE ecanp required the packet will have to go through a 
longer forwarding process(more lookups) and performance will be reduced. I 
don't have any solid numbers but my guess is that forwarding rate would be 
approx 1/2.

The part I am not sure about is if egress replication is still possible. In the 
mVPN scenario only ingress replication is possible due to the GRE encap/decap 
but I am not sure if this same limitation applies to P2P GRE tunnels. Let me 
know if this piece would be important to you and I can look into it. 

The one caveat to be careful of here(applies to unicast as well) is that each 
GRE tunnel must be sourced from a unique IP address on the box. Using the same 
source IP on more than one GRE tunnel will cause all traffic in GRE decap path 
to be punted to CPU and maybe multicast on encap path in some scenarios. 

-Ben



~
  ..  Benjamin Lovell
  ||  AS Video Practice
 |||  ||| Cisco Customer Advocacy
   .|.  .|.   Research Triangle Park, NC
.:|:..:|:.Email:  belov...@cisco.com
 ciscodesk:919.392.8255 cell:203.509.1562
~

On Sep 28, 2010, at 10:02 AM, John Neiberger wrote:

> I have an architectural question. As an example, let's say you have
> two 7600s directly connected via routed links running PIM and you have
> primarily multicast traffic. If you're running egress replication
> mode, you either have a Janus ASIC or Metropolis ASIC responsible for
> the multicast replication, which happens on the line card. But how
> would things change if you were not running multicast directly on the
> routed link, but instead used a GRE tunnel between the two routers?
> 
> I guess I have a couple of questions:
> 
> 1. How is GRE traffic processed in this scenario? Can it be forwarded
> at high rates on the line card or is it punted to the CPU?
> 
> 2. Which hardware is responsible for multicast replication over GRE tunnels?
> 
> Any ideas?
> 
> 
> Thanks!
> John
> ___
> cisco-nsp mailing list  cisco-nsp@puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/

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[c-nsp] Multicast replication over GRE on 7600s

2010-09-28 Thread John Neiberger 
I have an architectural question. As an example, let's say you have
two 7600s directly connected via routed links running PIM and you have
primarily multicast traffic. If you're running egress replication
mode, you either have a Janus ASIC or Metropolis ASIC responsible for
the multicast replication, which happens on the line card. But how
would things change if you were not running multicast directly on the
routed link, but instead used a GRE tunnel between the two routers?

I guess I have a couple of questions:

1. How is GRE traffic processed in this scenario? Can it be forwarded
at high rates on the line card or is it punted to the CPU?

2. Which hardware is responsible for multicast replication over GRE tunnels?

Any ideas?


Thanks!
John
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