Question

Edge closet design

  • 13 November 2020
  • 15 replies
  • 114 views

We’re getting ready to refresh a significant number of edge closets and are looking to change up a few things. Our primary goals are:

  • Support 2.5/5gbps links for our WAPs.
  • Reduce/eliminate total downtime of the wired network and wireless network
  • Save money

The current thought is to do something like the following:

  • Place 2 higher-end switches capable of multi-gigabit links to handle the WAPs (max ~20 APs/closet)
  • Fill out the remaining port needs with lower-end PoE switches

The question is, what’s the best way to accomplish the first 3 points following the second two. My initial thought would be to take the two higher-end switches (either 5520s or x465s) and set them up as an MLAG and the lower-end switches (either x440s or v400s) as a “stack” (with the understanding that V400s don’t actually stack and assuming that V400s can be uplinked to an MLAG). This should allow any one of the 3 entities to go down for whatever reason (hopefully just firmware updates) without taking the other 2 down.

Diagram of what I think is a good idea until people tell me why I’m being dumb:

 

Am I missing anything? I understand that nothing benefits from the MLAG except for the stack and the uplink to the core. Is there a better way to accomplish what I’m after?


15 replies

Userlevel 4

Am I missing anything? I understand that nothing benefits from the MLAG except for the stack and the uplink to the core. Is there a better way to accomplish what I’m after?

Correct. If the X440 (I prefer them over V400) Stack is connected via MLAG to “Closet-Switches” it will stay online if you reboot the “closet-switches” one by one (e.g. for an firmware upgrade)

I don’t think that you can connect one WAP to both switches because, they all have only one PoE-Port afaik (and offer only one MultiGig Port) So you don’t have any high-availability for your access-points. 

To reduce the downtime during a hardware failure, reboot, firmware upgrade… you might have to distribute the WAPs evenly on both switches, so that the users always have two WAPs near them, each on a different switch.

Am I missing anything? I understand that nothing benefits from the MLAG except for the stack and the uplink to the core. Is there a better way to accomplish what I’m after?

Correct. If the X440 Stack is connected via MLAG to “Closet-Switches” it will stay online if you reboot the “closet-switches” one by one (e.g. for an firmware upgrade)

I don’t think that you can connect one WAP to both switches because, they all have only one PoE-Port afaik (and offer only one MultiGig Port) So you don’t have any high-availability for your access-points. 

To reduce the downtime during a hardware failure, reboot, firmware upgrade… you might have to distribute the WAPs evenly on both switches, so that the users always have two WAPs near them, each on a different switch.

I went back and forth about whether I should include that detail. Every WAP (or other wired device) that gets plugged into the 5520/465 will only be single-link devices, so I understand that I’ll lose everything connected to that switch when it goes down. As you said, the idea would be to evenly distribute WAPs so that with one switch down, the closest WAP to that one is still up.

Userlevel 6
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Hello,

Unfortunately you do not write which WAPs should be used. But if you use current AX-APs e.g. together with the XCC, then "SmartRF" in the XCC ensures that exactly such failures are compensated. To do this, the WAPs must be close enough to each other so that in case of a failure (e.g. software update of a switch) the transmission power can be increased to close the gap.

In addition, some AX models allow the second Ethernet port to be used as a backup on a second switch.

Userlevel 4

Hi, 

In addition, some AX models allow the second Ethernet port to be used as a backup on a second switch.

the APs I checked support PoE only on one of the interfaces, so the backup port doesn’t really help, since the AP will be powered off. Or do I miss something? 

Userlevel 6
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Hello Stefan,

I have not tried it, but according to the Quick Reference Guide for AP510Ie you can provide redundant power via both ethernet ports:

https://documentation.extremenetworks.com/wireless/QRG/9035993-02_AP510i_QuickRef.pdf?_ga=2.18747568.869456194.1604868696-1757759156.1597658815

 

 

Userlevel 4

Good to know. I checked the tech specs before and there it is written:

Interfaces•

(1) 100/1000/2500/5000 Mbps auto-negotiation Ethernet port, RJ45 PoE (Power over Ethernet 802.3at) Port. (802.3bz supported)•

(1) 10/100/1000 Mbps auto-negotiation Ethernet port, RJ45

 

Only for one of the two interfaces PoE is listed. Strange.

Best regards
Stefan

Userlevel 6
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Strange indeed,

in addition on the product page:

https://www.extremenetworks.com/product/ap510ie/

There is a hint regarding redundant poe (search for redundant on the web page).


I have opened a GTAC case and will write here what comes out of it.

Userlevel 6
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Here is a small update:


The GTAC confirms the different statements in the documents and will clarify them with the product management.
 

Hello,

Unfortunately you do not write which WAPs should be used. But if you use current AX-APs e.g. together with the XCC, then "SmartRF" in the XCC ensures that exactly such failures are compensated. To do this, the WAPs must be close enough to each other so that in case of a failure (e.g. software update of a switch) the transmission power can be increased to close the gap.

In addition, some AX models allow the second Ethernet port to be used as a backup on a second switch.

Yeah, my concern was specifically around making sure the switch design (mlag ↔ mlag ↔ stack) would work and that there wasn’t a better/different way to accomplish what I think we want to. The APs will be HPE/Aruba 500 series, which have 2 ethernet ports that can be configured as an LACP group, but in most of our environment, it’s not really worth the added overhead to build it out that way, especially since we don't have the structured cabling to support that today.

Userlevel 6

Are your APs actually going to push more than 1Gbps? Most client devices are 2SS and don’t support MU-MIMO so even on a 40MHz channel the max data rate under 600Mbps. There is the argument for futureproofing for wifi 6E which will allow wider channels but that’s still a couple of years away and even then most environments aren’t going to exceed 1Gbps per AP IMHO. If you do have environments running 80MHz channels with 3SS clients then it’s possible, but it’s by no means the general case.

Are your APs actually going to push more than 1Gbps? Most client devices are 2SS and don’t support MU-MIMO so even on a 40MHz channel the max data rate under 600Mbps. There is the argument for futureproofing for wifi 6E which will allow wider channels but that’s still a couple of years away and even then most environments aren’t going to exceed 1Gbps per AP IMHO. If you do have environments running 80MHz channels with 3SS clients then it’s possible, but it’s by no means the general case.

The short answer is: probably. We generally upgrade our networking equipment every 7-10-ish years. So we have to think about what the environment is going to look like in 5 years, when there’s been enough time for significant change in end user technology because we still have multiple years before the next refresh. We’re a medical school and healthcare facility, so we have some significant device-dense areas, bandwidth intense applications (VDI, Citrix, telehealth, virtual classrooms, remote lecturers, Netflix, spotify), and patient care critical devices (though we’re not a hospital, so not life/death level critical). Couple that with a significant group of endusers (students) who expect to walk in with the latest and greatest devices and have the best experience.

 

The spec sheet of the APs we’re moving to says this:

  • P type: Indoor, dual radio, 5GHz and 2.4GHz 802.11ax 4x4 MIMO
  • 5GHz radio: Four spatial stream Single User (SU) MIMO for up to 2.4Gbps wireless data rate with individual 4SS HE80 (or 2SS HE160) 802.11ax client devices, or with four 1SS or two 2SS HE80 802.11ax MU-MIMO capable client devices simultaneously
  • 2.4GHz radio: Four spatial stream Single User (SU) MIMO for up to 1,150Mbps wireless data rate with individual 4SS HE40 802.11ax client devices or with two 2SS HE40 802.11ax MU-MIMO capable client devices simultaneously

That seems to indicate that you can exceed 1gbps by a lot with 2SS devices and 80MHz channels

Userlevel 6
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Hello,

now I have a final answer from GTAC:

The AP510 supports redundant power via PoE.

Userlevel 6

The spec sheet of the APs we’re moving to says this:

  • P type: Indoor, dual radio, 5GHz and 2.4GHz 802.11ax 4x4 MIMO
  • 5GHz radio: Four spatial stream Single User (SU) MIMO for up to 2.4Gbps wireless data rate with individual 4SS HE80 (or 2SS HE160) 802.11ax client devices, or with four 1SS or two 2SS HE80 802.11ax MU-MIMO capable client devices simultaneously
  • 2.4GHz radio: Four spatial stream Single User (SU) MIMO for up to 1,150Mbps wireless data rate with individual 4SS HE40 802.11ax client devices or with two 2SS HE40 802.11ax MU-MIMO capable client devices simultaneously

That seems to indicate that you can exceed 1gbps by a lot with 2SS devices and 80MHz channels

I was about to say that MU-MIMO support is non-existent outside of phones, but now I see the Intel AX200 supports MU-MIMO so perhaps that will change. Do remember that 2.4Gbps is the data rate, not the achieved throughput. I also tend to discount 80MHz channels and 2.4GHz but the former will become relevant with wifi 6E APs. You’ll be upgrading your APs before 7 years BTW, Extreme drops AP software support 2 years after end-of-sale (which is too early IMHO, but that’s another argument). But if your switches need to last that long then 2.5Gbps ports for APs are probably worth it.

The spec sheet of the APs we’re moving to says this:

  • P type: Indoor, dual radio, 5GHz and 2.4GHz 802.11ax 4x4 MIMO
  • 5GHz radio: Four spatial stream Single User (SU) MIMO for up to 2.4Gbps wireless data rate with individual 4SS HE80 (or 2SS HE160) 802.11ax client devices, or with four 1SS or two 2SS HE80 802.11ax MU-MIMO capable client devices simultaneously
  • 2.4GHz radio: Four spatial stream Single User (SU) MIMO for up to 1,150Mbps wireless data rate with individual 4SS HE40 802.11ax client devices or with two 2SS HE40 802.11ax MU-MIMO capable client devices simultaneously

That seems to indicate that you can exceed 1gbps by a lot with 2SS devices and 80MHz channels

I was about to say that MU-MIMO support is non-existent outside of phones, but now I see the Intel AX200 supports MU-MIMO so perhaps that will change. Do remember that 2.4Gbps is the data rate, not the achieved throughput. I also tend to discount 80MHz channels and 2.4GHz but the former will become relevant with wifi 6E APs. You’ll be upgrading your APs before 7 years BTW, Extreme drops AP software support 2 years after end-of-sale (which is too early IMHO, but that’s another argument). But if your switches need to last that long then 2.5Gbps ports for APs are probably worth it

We don't purchase extreme wireless products, it's all HPE/Aruba and they do not APs that quickly. Our current APs were purchased in 2013.

 

Userlevel 6

In that case I’d chat with your wireless team and ask when they expect to refresh the APs and what channel size they expect to use.

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