Ask the Expert: Cisco Wireless LAN Controllers (WLCs) - Page 4

ciscomoderator · ‎06-11-2013

with Cisco Expert Nicolas Darchis

Welcome to the Cisco Support Community Ask the Expert conversation. This is an opportunity to learn and ask questions about how to trobuleshoot, configure and deploy any Cisco Wireless LAN controller with Cisco subject matter expert Nicolas Darchis.

Nicolas Darchis is a wireless and authentication, authorization, and accounting expert for the Technical Assistance Center at Cisco Europe. He has been troubleshooting wireless networks, wireless management tools, and security products, including Cisco Secure Access Control Server since 2007. He also focuses on filing technical and documentation bugs. Nicolas Darchis holds a bachelor's degree in computer networking from the Haute Ecole Rennequin Sualem and a master's degree in computer science from the University of Liege. He also holds CCIE Wireless certification number 25344.

Remember to use the rating system to let Nicolas know if you have received an adequate response.

Nicolas might not be able to answer each question due to the volume expected during this event. Remember that you can continue the conversation on the Wireless sub-community, Getting Started with Wireless discussion forum shortly after the event.

This event last through Friday June 28, 2013. Visit the community often to view responses to youe questions of other community members.

robertssean · ‎06-21-2013

Hi,

Question regarding USB ports 0 & 1

Can these ports be used? If so how are they enabled? I have a USB drive in port 0 but n green light on, is there something I am missing? My wlc 5508 is running ver 7.2.11.3

Cheers

sean

Nicolas Darchis · ‎06-21-2013

http://www.cisco.com/en/US/docs/wireless/controller/release/notes/crn6_0_196.html#wp534673

USBs are used as console only. No other use were given to them so far.

Regards,

Nicolas

Rasika Nayanajith · ‎06-21-2013

Hi Nicolas,

When we configuring DHCP option-82, we normally enable it for dynamic interfaces where users are connected.(to get an idea about point of attachment of a user).

In Auto-Anchor configuration for guest users do we need to enable this on management interface (where guest WLAN is map to management interface on foreign controllers) of foreign WLCs ? Or do we only need to configure it on Anchor Controller dyanamic interface where guest users get an IP ?

Rasika

Nicolas Darchis · ‎06-21-2013

Option 82 is not yet supported in anchor scenario. The problem is that it's the anchor doing DHCP and it's the foreign having the ap mac address information.

It is not entirely impossible as you could imagine the foreign WLC "telling" via mobility protocol the anchor about the current AP mac address, but it is not happening at this stage. I heard several customers request it but did not hear it coming as a new feature soon.

Rasika Nayanajith · ‎06-21-2013

Hi,

Which version of the WLC code (for 5508, 3850 & 5760) will support 802.11ac for 3600 AP with .11ac module ?

Rasika

Nicolas Darchis · ‎06-21-2013

7.5 on 5508 and similar

the 3850/5760 run a different kind of code and do not support 11ac at this time. I don't have the information on the availability there. I would guess in the coming release though.

patrick.kofler · ‎06-21-2013

Hi Nicholas,

I'll post this question separately as it does not relate to the previous inquiry.

There are two boot modes for the NGWCs 5760/3850 - Bundle and Install.

When I read the documentation it seems the bundle mode does not yield any advantages over the install mode, in fact it has some limitations to it like AP Image predownloading not supported.

This leaves me the question why this mode actually exists?

Can you please elaborate a bit more on the bundle mode?

Thanks!

Regards,

Patrick

Nicolas Darchis · ‎06-22-2013

Booting into Install mode is fast and light in terms of memory consumption, but 
booting from usbflash0: or via tftp is not supported.
Bundle mode is booting a monolithic IOS image. Additional memory is used when 
booting into Bundle mode, however, this mode supports booting from flash:, 
usbflash0:, or via tftp.

5760 only supports install mode, bundle is only available on 3850.

When Install Mode is used and recovery is needed (for example, the 
installed image in flash is corrupted), emergency recovery procedures are 
defined to get an image over  tftp to re-install.

I hope this clarifies. Not much use for bundle mode thus :-)

Rasika Nayanajith · ‎06-21-2013

Hi,

I have read 7k is the client limit for a 5508. What is the limiting factor & what will happen if we have more than 7K client for a given controller ?

We have multiple 5508 WLCS with 4 dynamic interfaces of /21 (2048 IPs in each vlan) totalling of 8K IPs for a one 5508. Since it is not using 100% we have not exceeded the 7K valule (but close to 5-6k at peak times).What are the scalability options available.(currently looking for 3850s & make 5508 central controller) ? How this 7K limit impact in that scenario ?

What would be the client limitation of a 5760 controller ?

Rasika

Nicolas Darchis · ‎06-21-2013

if you have more than 7000 clients, the extra clients will never associate as the client table has only 7000 entries.

5760 supports 12000 clients as documented here :

http://www.cisco.com/en/US/docs/wireless/controller/3.2_0_se/release_notes/OL28115_3_2_se_rn.html

Your scalability options could simply be to buy a 2nd 5508. What prevents you from that ? They can all have 4 dynamic interfaces in the same subnet as each other.

Rasika Nayanajith · ‎06-21-2013

Hi Nicolas

8x1G capacity is the main limitation with this 5508 platform. Also we cannot connect it to two different switches 4G+ 4G for redundancy . If we etherchannel all has to go to a single switch as one 8G.

Is there any plan to add 10G interfaces to 5508 platform ? else 5508 will be phased out making 5760 is the controller to go with.

Regards

Rasika

Nicolas Darchis · ‎06-22-2013

5760 is indeed the controller of the future. But it does not have feature parity yet and the 5508 generation has still some time to keep on living (many new versions are to come for that platform).

In the same generation as 5508, the Wism2 has 2 10Gig ports. 5508 will thus not evolve.

You can absolutely connect a 5508 4G + 4G to two different switches if those switches are 2 6ks in VSS or 2 nexus in VPC.

But I still don't understand your original point. If you have 6000 clients on your 5508, why wouldn't you be better with 2 5508 ? You would have redundancy for your APs if one fails. You could connect them to different switches. That would make 16gig total bandwitdh ... I don't see any drawback there

Rasika Nayanajith · ‎06-23-2013

Hi Nicolas,

I can simply add more 5508s (currenlty we have 9 of them). But I would like to make sure it is the best investment as at today. we purchased those 5508 in 2-3 years back & unless this product has a clear future (which I do not see) ,we do not like to invest heavily on that product platform.

In that sense I am happy to wait 5760 to get the feature parity & then complement with 3850s in Access layer. 802.11ac around the corner & will influence in these decision. I do not want WLC to become a bottleneck in our infrastructure. I am in a University environment & infrastrcuture scalability is a key criteria. (Currently running with 1.5k APs & 12K concurrent devices & bandwidth demand is growing in rapid phase

Rasika.

gnijs · ‎06-25-2013

What about a 8500 controller ?

Nicolas Darchis · ‎06-25-2013

It is Flex-Oriented like the 7500