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New Member

6500-design ports for 2 modules

Hi Ciscoers,

I have 2 cores 6513 equipped with 2 modules which each having x16 SF ports.

2 cores connects to about 9 Dist Switches as active and 9 DistSwitches as passive (typical cisco design for HSRP).

Which:

-CoreA should have 2 legs to Dist_A and Dist_B

-CoreB has 2 legs also to Dist_A and Dist_B

How is the best practice  to allocate of using ports to have balance/sharing the load?

Thanks&Regards,

sam

11 REPLIES
VIP Super Bronze

Re: 6500-design ports for 2 modules

Hi Sam,

You also need a link between core-1 and core-2, so if for example the connection from one of the distro-switch-1 to core-1 goes out, you get rerouted through core-2 and back to the distro-switch-1

HTH

Reza 

Hall of Fame Super Silver

Re: 6500-design ports for 2 modules

Hello Sam,

>> How is the best practice  to allocate of using ports to have  balance/sharing the load?

interconnect the two cores with a 4 GE port channel as suggested by Reza using 9/1, 9/2, 10/1, 10/2 for the reasons explained below

create a 2GE port channel towards each distribution using ports 9/x and 10/x for each bundle.

if possible do the same, that is use ports of different modules on distribution switches.

so if a linecard fails you still have a member link towards each device if you use ports on the same module when the module fails you miss 5 switches.

Edit:

if you specify what line card model  is involved the exact model is also possible to evaluate if there is oversubscription or not in using 11 ports out of 16.

Hope to help

Giuseppe

New Member

Re: 6500-design ports for 2 modules

Hi Giuseppe,

Many thank for you all prompt responses.

interconnect the two cores with a 4 GE port channel as suggested by Reza using 9/1, 9/2, 10/1, 10/2

-> Means, 2 phyiscal connection having 4 logical logical link right? and it should use 4x10 G link ?

create a 2GE port channel towards each distribution using ports 9/x and 10/x for each bundle.

-> Your idea is refering to which pictures attached? (option1 or option2?)

Note, DistA is Active distB is stanby

Regards,

sam

VIP Super Bronze

Re: 6500-design ports for 2 modules

Hi Sam,

interconnect the two cores with a 4 GE port channel as suggested by Reza using 9/1, 9/2, 10/1, 10/2

-> Means, 2 phyiscal connection having 4 logical logical link right? and it should use 4x10 G link ?

No, it means if you have 4 extra physical links put them all in one etherchannel. You don't have to put 4, you can just put 2 10Gig and that also would be sufficient.

create a 2GE port channel towards each distribution using ports 9/x and 10/x for each bundle.

-> Your idea is refering to which pictures attached? (option1 or option2?)

It means create one etherchannel with 2 physical links in it (one from each module) to the primary distro switch and  create another etherchannel with 2 physical links in it (one fron each module) to the back up distro switch.

HTH

Reza

Blue

Re: 6500-design ports for 2 modules

Sam, Reza and Giuseppe have given you some good advice, but I would like to add a thought or 2.

First, you don't just make connections arbitrarily and create port-channels off the top of your head without an understanding of what your requirements are.

You have to have a good idea of the amount of traffic that is flowing in your network and how it flows.

Second, when you want to implement a design solution that includes redundancy, you have to consider link redundancy, chassis redundancy, module diversity, power and environmental redundancy, cable diversity, etc. The point is to create a design that eliminates single points of failure and provides as much stability and reliability as possible.

Just keep these ideas in mind as you create a design.

Lastly, as far as the number of ports to include in your etherchannels, that goes back to understanding the data flows and data rates in your network. No one can just tell you how many ports to include without any knowledge of the traffic requirements.

HTH

Victor

New Member

Re: 6500-design ports for 2 modules

Hi Giuseppe

The line Cards will be used  WS-X6716-10G-3C

Thanks&Regards,

Sam

Hall of Fame Super Silver

Re: 6500-design ports for 2 modules

Hello Sam,

if the linecard is WS-6716 10GE I would consider to first deploy a single link between each access layer switch and distribution/core.

My first answer was based on the assumption that the ports were simple GE and not tengiga ports.

Be also aware that WS-6716 can work in two ways:

- oversubscription 4:1:  communication with sup720 Gbps switching fabric happens at 40 Gbps "only", making the oversubscription ratio 4:1 you cannot use all the 16 tengiga ports at wire speed at  the same time. I would not expect local switching capabilities so this is the limit.

- dedicated mode only one port every 4 can be used this is typically used to build a VSS pair.

Given the notes above about  the linecard I would use a single port to each access layer switch and a 2 X Tengiga port channel between core / distribution switches.

Take also in consideration what Victor says: only you knows the details about  traffic patterns and expected traffic volumes, we can give suggestions but we don't know all these details.

So for example if it is a serverfarm I would  try to use less ports per module as possible in order to have the best performance.

If it is simply a campus network you could also start by using all ports of a single module.

Hope to help

Giuseppe

New Member

Re: 6500-design ports for 2 modules

Hello Giuseppe,

I will be  using :

-LineCards: WS-C6716-10G-3C  (x2)
-SUP : VS-S720-10G-3C

As mentioned ealier, the line cards will support about 20 D-S behind (x10-DistA and x10 DistB).

Any issue of oversubscription 4:1 ratio?

Again many thanks for your kind helps.

Regards,

Sam

Hall of Fame Super Silver

Re: 6500-design ports for 2 modules

Hello Sam,

>> Any issue of oversubscription 4:1 ratio?

you have 32 ports in two C6716 and you need to use 20 ports of 32 you are clearly going to take in account oversubscription in your design.

Again, if this is a campus network with end users at access layer this is acceptable and we use it, if you are building a server farm this is less acceptable

Just to say we are building a new server farm and we use only 4 ports on a WS 6716 to connect to a Nexus (a nexus pair).

the Nexus has then all the 10GE uplinks of access layer switches (4948) because it has higher port density.

Hope to help

Giuseppe

New Member

Re: 6500-design ports for 2 modules

Hi Giussepe,

Coming again, the port-WS 6716  can be used for port channeling between 2 Cores?

I am planning to use :

Core-1 port GiX/1 and Gi(X+1)/1 to Core-2, port GiX/1 and Gi(X+1)/1, is it enough to have 2 physical connection for port channeling?

What happens if having 4 physical connection?

Note: I have 2 modul WS 6716, so I use X -Upper and X+1 for below .

Many Thanks in advance,

Sam

Hall of Fame Super Silver

Re: 6500-design ports for 2 modules

Hello Sam,

>> Coming again, the port-WS 6716  can be used for port channeling between 2  Cores?

yes you can do so, and it is wise to use links from both linecards to build the bundle

Hope to help

Giuseppe

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