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Ask the Expert- SD-WAN

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Beginner

New Core Switches

Hello I am looking to get an expert opinion on what equipment our company should buy for our core switches.  We currently need to replace 2 of our core 6509 as they are end of life with new equipment and will need to decide if we should stack use stacked 3850s for the core or to buy new chassis or cards for the 6509.  Our network currently has around 12 distribution layer switches and over 350 access layer switches.  Thanks for your help.

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VIP Advisor

Re: New Core Switches

Basically performance, density port, IOS features and throughput. Check this link: https://www.cisco.com/c/en/us/products/switches/campus-lan-switches-core-distribution/index.html#~stickynav=2

 

Also clic Upgrade bottom on this link: https://www.cisco.com/c/dam/assets/prod/switches/cisco-switch-selector-how-to/index.html#/campus?oid=otres000315

 

The 3850 could work as Core for small companies where the demand is not high. 

 

Hope it is useful

:-)

14 REPLIES 14
VIP Mentor

Re: New Core Switches

Personally if your core dist/access layer is that big i wouldnt be using a stack of 38s as the core definitly , the new replacments for 65s were the 68s and now its the new campus 9000 series switches , i would be looking at them 9400s , 6880s are going and being replaced with these switches , there very powerful but then again it all comes down to budget , but if the choice is there i would look at these , im hoping to replace my VSS with these eventually  when our ILCM comes up

 

https://www.cisco.com/c/dam/en/us/products/collateral/switches/catalyst-9300-series-switches/nb-09-cat-9k-aag-cte-en.pdf

VIP Advisor

Re: New Core Switches

Hi,

You could consider the 68xx or the new models 9000. Everything depends of the type of traffic, port density and type that you are going to replace, for example you can select a Cisco 9500 because you could request all the ports for SFPs, but as I mentioned previously it depends of your current infrastructure specs and the growth of your company in a future.

I suggest visit this site and check the recommendations for the replacements.

https://www.cisco.com/c/dam/assets/prod/switches/cisco-switch-selector-how-to/index.html

 

Please don't forget to rate or mark as answered if it was useful

:-)

Beginner

Re: New Core Switches

Thank you for the replies.  Is there a reason why we should not go for the stacked 3850s over the 68xx or 9000?  We are trying to justify the need for the those two switches over a stacked 3850 for the core.  Thanks again for your help.

VIP Advisor

Re: New Core Switches

Hi 

I think you should not go to 3850 instead of 6500, basically you will be doing a downgrade. The 3850 are very good switches but they cannot handle the throughput or traffic like the 6500's. 

My personal opinion, you should consider the 9000 series to replace the 6500. They are new ones with better technology. 

Beginner

Re: New Core Switches

Do you know of any reasoning that we can push towards management as to why the 3850s are a bad idea? They believe it is adequate for the our network and we are trying to write a justification on why we should not go towards that route.

VIP Advisor

Re: New Core Switches

Basically performance, density port, IOS features and throughput. Check this link: https://www.cisco.com/c/en/us/products/switches/campus-lan-switches-core-distribution/index.html#~stickynav=2

 

Also clic Upgrade bottom on this link: https://www.cisco.com/c/dam/assets/prod/switches/cisco-switch-selector-how-to/index.html#/campus?oid=otres000315

 

The 3850 could work as Core for small companies where the demand is not high. 

 

Hope it is useful

:-)

Enthusiast

Re: New Core Switches

I'm not keen on a stacked core unless, as Julio says, it's a small company. Seen too many stack failures over the years. I'd prefer a pair of standalone L3 switches, provided you can provision a routed-only core.

I suppose the same concerns should apply to VSS because it's a single control plane but VSS does generally seem very stable (based on customer feedback and speaking to our support centre).

Cisco is really pushing the 9K - it seems to be the default answer to any question. That's fine and the 9K is likely the best long-term choice for many, but you just need to be a bit careful. 

It's early days for me spec'ing these switches but they seem to be missing quite a lot of functionality. Today I've been looking at a dual 9500-40X core and trying to work out what tools the customer will have for a core upgrade. Doesn't seem to be much on offer. For example, the Graceful Insertion and Removal (GIR) feature is only available with ISIS. And we can't spec ISIS cos we need to keep the costs down and the Essentials lic (on 9300 edge) will only support OSPF for Access or Stub EIGRP. Happy days.

Contributor

Re: New Core Switches

With the Catalyst 9400 not supporting VSS, how could it be considered ready for a core?  The roadmap for it having VSS is a year or so, correct?  

 

Also, with the Cat9Ks only shipping for a few months, and very limited numbers of deployments, and being deployed in a production environment for a very short time frame, I would be tentative about recommending the C9Ks for a production environment where high up time is a requirement.   There are limited releases of code (16.6.1 & 16.6.2) available for the C9Ks, which is a limiting factor to consider if a bug is encountered.  With more seasoned platforms, there are long lived code trains with recommended releases.

 

Stackwise virtual is new, again with limited deployment and not supported on all models.  Just the 9500-24Q at the moment.

 

The Cisco CVDs and design guides make no reference to Catalyst 9Ks, they recommend the Catalyst 6807 or Nexus 9K.  

 

With Quad Supervisors, on a pair of Cat6Ks or N7Ks, software upgrades or supervisor failures can occur with virtually no downtime, perhaps a few pings will drop.   (A properly designed and configured implementation is required, and there are certain upgrades that could be more challenging-if the N7k lines cards need an EPLD upgrade for example).   However, Cat6Ks or N7Ks have been rock solid for years, have all of the high availability features that an enterprise network requires, and have been proven to deliver superior up time, and resilience during component failures and upgrades.

 

Upgrading a Cat9K, or a supervisor failure is going to be a much more significant outage without VSS, ISSU, and the limitation from the 16.6.2 release notes I reference below-several minutes I believe. 

 

****************

"Redundancy—The supervisor module (hardware) supports redundancy. Software redundancy is supported in IOS XE Everest 16.6.2. The associated route processor redundancy (RPR) feature is currently not supported."

 

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9400/software/release/16-6/release_notes/ol-16-6-9400.html

***************

 

Regards, Jason

Highlighted
Contributor

Re: New Core Switches

Hmm, I never have dictated to anyone whether on the customer side as an architect, manager, director or now on the pre-sales engineering size.   I can inform and advise based upon my experience and knowledge gathered from my fellow pre and post sales engineers.

 

I agree that the cost of a solution has to meet the budgetary, security, and operational availability requirements of the project / customer.  The engineers that work for the organization and for vendors / VARs need to take those above items into account when creating a design.  A network infrastructure cannot exceed the budget, or be a massive overkill for what the business requires.

 

A Catalyst 6807 with quad core, Nexus 7700/9500 with dual supervisors, etc. is, of course, for large enterprise campus or data center cores that support significant numbers of users, storage, compute, or remote sites, etc. is a solution that should be considered when the highest level of uptime and stability are a requirement.

Re: New Core Switches

I wouldn't build a core existing of 1 stack... to my knowledge you cannot upgrade a (3850) stack without full downtime...

So that would require at least 2 stacks or 2 standalone devices which requires spanning-tree blocked interface(s). VSS or vPC might be a better solution. Actually the 4500X is also a good competitor for 3850 (depending on the 3850 model): they support VSS and are 10Gbps.

 

Jeroen

Hall of Fame Community Legend

Re: New Core Switches

Cisco has released new series of switches:  Catalyst 93009400 and 9500.

The 9300 will be the direct replacement of the 3650 & 3850. 

The 9400 will be the direct replacement for the entire 4K series, including 4500X. 

The 9500 will be the direct replacement for the entire 6K series, including 6500 and 6800 family of switches.  

Have a look at this to ensure the network investment isn't going to waste.

Everyone's tags (3)
Rising star

Re: New Core Switches

 

 - Better to execute the migration project with a reseller, as they can handle lots of practial things such as migration path, detailed part(s) ordering, etc...

M.

VIP Expert

Re: New Core Switches

Could you use a stack of 3850s for your core? Perhaps, but the real question is whether they would work well for you. If you're wondering why, it's because there's much more to any switch then how many ports it supports at a particular bandwidth.

For your 6509s, I assume you're well acquainted that not all cards offer the same performance or features, whether it's a supervisor line card or a Ethernet line card. For example contrast a 6513E with sup32/sup1/sup2/sup720 having all classic bus line cards vs. a 6513E with a sup2T and having all 80GB fabric line cards with DFCs.

The 3850 wasn't designed to be support the same level of performance that can be obtained on other Cisco devices.

What cannot be easily determined by your question and the additional information you provided is whether you need the performance or features that 3850s do not provide.

VIP Expert

Re: New Core Switches

BTW, an example of why chassis devices are often recommended for critical usage, like network cores: https://supportforums.cisco.com/t5/lan-switching-and-routing/cisco-3850x-boat-anchor/m-p/3005183#M371817

Besides often having more capacity and features, vendors often give chassis devices a bit more attention insuring they work correctly.

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