Network Readiness Assessment - Avaya to Cisco Migration

[Carlos Aguinaldo]

Hi Team,

We ( the network team) along with the voice team have an upcoming migration as stated above. I am tasked to generate a Network Readiness Assessment report. We have three sites that will undergo voice migration from Avaya to Cisco phones. We have a CUCM cluster in a different DC in which the phones will connect to via MPLS.

Site 1 - 350 phones

Site 2 - 80 phones

Site 3 - 30 phones

All voice equipment (voice routers, phones, licenses, etc.) have already been purchased. My question is, does anyone have a template for a network readiness assessment? Or perhaps some inputs on how to generate one? I've googled and was not able to found anything relevant.

I already generated some parameters based on the following.

Subnets - Are there sufficient subnets for parallel migration?

LAN QoS - is the current policy applicable?

WAN QoS - is the current policy applicable?

WAN BW - will the WAN bandwidth suffice?

Route advertisment - are the new subnets already advertised to the WAN?

Is there anything I'm missing?

Thanks in advanace.

[Rajan]

Hi Carlos,

Few things to add to what you have drafted.

- Make sure Round Trip Delays are good enough (<=80ms) if the CUCM servers in the cluster are distributed across WAN

- IF firewalls are involved, make sure that the required ports are open for communication

HTH

Rajan

[Carlos Aguinaldo]

Thanks for the feedback. Do you recommend a specific tool determining the RTT? Or will a simple trace suffice?

[Dennis Mink]

Carlos, 

as far as I know there is no special tools for this, just get any icmp poller, like solarwinds or anything, and poll it like every minute for a period of time, this will give you a good idea of you median RTT, average, max etc.

also, have you thought about DHCP scopes and option 150 dished out to the phones? 

[Carlos Aguinaldo]

Hi,

Yes, I've incorporated DHCP scopes in the "new subnets" part. Apart from the parameters I've posted in my OP and Rajan's suggestion, do you think I have to add more to it?

[Mohammed al Baqari]

Hi,

Couple of points which I can think about:

1. Network High Availability (typically MPLS to DMVPN). Important to have redundant path when your primary WAN is down

2. Network Monitoring (Netflow and SNMP). You need to make sure that you can monitor all nodes across the network to identify points of failure and degradation

3. Concurrent Calls estimate during Busy Hours (based on ErlangB or ErlangC). It is good to have an estimate of the calls failure rate during busy hours. This depends on available BW and selected codec along with your grade of service

4. Think about WAN Security and how important that for your company (you might need to encrypt the WAN traffic using IPSec Tunnel over MPLS)

There are other aspects to consider but I believe your question is directly related to network infrastructure

[Carlos Aguinaldo]

Hi,

Thanks for the inputs.

1. We will be migrating these sites to our iWAN infra after this project. So we're good with HA.

2. We will be polling the devices via Solarwinds.

3. If I'm not mistaken, I have to determine the number of calls during busy hours and multiply that with 100 Kb (G.711) to determine if our WAN EF is enough right?

4. This will be covered once migrated to iWAN.

[Mohammed al Baqari]

The BW allocated to G711 is more than enough (over MPLS g711 can use around 93 kbps). You are right in multiplying BW by number of calls

[Carlos Aguinaldo]

Thanks Mohammed. By the way, Site 2, which has 80 phones has wireless phones. Any tips regarding what I should look out for?

[Mohammed al Baqari]

Hi,

The most important thing is WiFi Roaming (moving from AP to AP within same subnet or different subnet). You need to make your WiFi network Roaming compatible with VoIP calls to avoid silent moments and degradation.

You can also verify WiFi (CAC Policing if used).

This doc might help

http://www.cisco.com/c/en/us/solutions/collateral/wireless/4400-series-wireless-lan-controllers/net_implementation_white_paper0900aecd804f1a46.html

[Carlos Aguinaldo]

Okay thanks. I'm now composing the table of contents of the assessment report. I'll follow up on this thread once I've made the draft and will post the contents as you guys might have more inputs. Thanks again.

[Carlos Aguinaldo]

And yes, you're correct that my question directly relates to the network infrastructure aspect.