topic Re: SDA Multi-site -transit / wireless delay in Software-Defined Access (SD-Access)

SDA Multi-site -transit / wireless delay

ali ezzat1 — Fri, 03 Apr 2020 18:08:17 GMT

Dears,

I need to know the restriction to design multi-site with ip- transit and the WLC locate in HQ not in the branches

What is the delay between Access points and WLC required through the WAN link?

Can AP act as WLC in the branch if can't achieve the delay to the HQ WLC?

note that DNA version 1.2.10 and fabric edge will be C-9300

Thanks,

Ali Ezzat

Re: SDA Multi-site -transit / wireless delay

Scott Hodgdon — Fri, 03 Apr 2020 18:47:58 GMT

ali ezzat1,

As the APs run in Local Mode when part of SD-Access Wireless, they need a maximum of 20ms round trip latency to the WLC. This is usually what determines the placement of the WLC at the remote site.

Also, a WLC (single or pair in SSO) can only be associated with 2 SDA Control Plane Nodes. Usually each site in a fabric will have 2 Control Plane Nodes for redundancy, and so a WLC (single or pair in SSO) will be associated with each site.

We do not support the Mobility Express (AP acting as WLC) capability with SD-Access Wireless.

It is recommended that you upgrade to the latest 1.3.x.x release , with appropriate IOS XE / AireOS for fabric nodes, from 1.2.10 . Please reference the SD-Access Compatibility Matrix at https://www.cisco.com/c/en/us/solutions/enterprise-networks/software-defined-access/compatibility-matrix.html for latest recommended code versions.

If you decide not to upgrade, everything I have said applies to 1.2.10 as well as 1.3.x.x .

Cheers,

Scott Hodgdon

Senior Technical Marketing Engineer

Enterprise Networking Group

Re: SDA Multi-site -transit / wireless delay

ali ezzat1 — Fri, 03 Apr 2020 19:27:29 GMT

Dear Scott,

Thanks for this info, it is very useful for me

but if i use Fabric in a box ( Border-control-edge- WLC ) so WLC can be C-9300 at the branch but it must be one switch in the branch can't be two fabric switch in the branch ( not stack) as i have some branches contain 3 switches and some branches contain 2 switch

first scenario :

- one switch i can use FIB

second scenario

- two or three switchs ( not stack ) , so i need border and control node and can't use FIB feature

is this true ?

Thanks,

Ali Ezzat

Re: SDA Multi-site -transit / wireless delay

Scott Hodgdon — Fri, 03 Apr 2020 21:18:20 GMT

Ali,

Scenario 1: Correct.

Scenario 2 : You can assign one switch as Fabric in a Box (FIAB) with WLC and then connect other 9300 as Fabric Edge.

Cheers,

Scott Hodgdon

Senior Technical Marketing Engineer

Enterprise Networking Group.

Re: SDA Multi-site -transit / wireless delay

ali ezzat1 — Fri, 03 Apr 2020 23:29:50 GMT

Dear Scott,

in scenario 2 is there is any PDF or CVD to do this as the last CVD said that FIB is supported only in one switch.

and to do this DNA must be the latest version or it is supported in 1.2.10

Thanks,

Re: SDA Multi-site -transit / wireless delay

Scott Hodgdon — Sat, 04 Apr 2020 02:58:16 GMT

Ali,

You need DNA Center 1.3.3.x for support of FIAB (with onboard WLC) and connected to Fabric Edges. With DNA Center 1.3.3.1 you can have FIAB connected to Fabric Edges with WLC in the Fabric Edge.

The last I knew, we were in process of updating guides with these new options for 1.3.3.x . The Release Notes for 1.3.1.x outline the Fabric Edge + Wireless support in the "Table 8. New and Changed Software Features in Cisco SD-Access, Release 1.3.1.0" (https://www.cisco.com/c/en/us/td/docs/cloud-systems-management/network-automation-and-management/dna-center/1-3-1/release_notes/b_cisco_dna_center_rn_1_3_1.html#concept_ebs_wdr_f3b)

Cheers,

Scott Hodgdon

Senior Technical Marketing Engineer

Enterprise Networking Group.

Re: SDA Multi-site -transit / wireless delay

Bernard Lara — Fri, 05 Jun 2020 17:09:51 GMT

Dear Scott,

Additional 50 bytes to 1500 MTU is used for VXLAN encapsulation for SDA distributed campus

Does it include the CAPWAP and other overhead inside VXLAN ?

We are planning to request our ISP for 1600 MTU to have centralized WLC in HQ for 6 branches where APs are installed, is it enough?

If ISP won't be able to increased it then we might have local WLC per site and IP-based as Transit.

Appreciate your response.

-Bernard

Re: SDA Multi-site -transit / wireless delay

Scott Hodgdon — Fri, 05 Jun 2020 19:29:17 GMT

Bernard Lara,

There are two pieces of this: AP to WLC and WLC to AP.

AP to WLC

As the destination of the CAPWAP tunnel is the WLC, this traffic will be passed in the underlay with no VXLAN header. The Fabric Edge will have a programmed route to the WLC, so it will bypass the LISP process.

WLC to AP

As the destination is the AP and the AP is seen as a client in the Fabric Control Plane, this traffic will be passed in the overlay with a VXLAN header.

The bottom line is that you will need to be able to support a packet that has (VXLAN Header) + (CAPWAP Header) + (Original Packet) when looking at MTU.

If you are doing central WLC, then it has to be all one fabric site (a site being defined by distinct Fabric Borders, Control Planes, Edges). You cannot connect two sites to a single controller. Also, remember that latency round trip from AP to WLC cannot be higher than 20ms, otherwise you will need a local controller and a separate fabric site for any site that exceeds 20ms.

Cheers,

Scott Hodgdon

Senior Technical Marketing Engineer

Enterprise Networking Group