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Dual WAN with UC540 - Best Supported Config?

What is the best supported option for dual WAN connectivity to a UC540?

We have a customer that has static IPs for system hosting & SIP trunking on a slower line and a secondary line that is faster they would like to use for PC connectivity and redundancy.

Introduce a SR520 behind the UC540?  Can CCM configure the SR520 for the redundant links?


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Re: Dual WAN with UC540 - Best Supported Config?

Marcos wrote a great article detailing how to configure your UC540 to have redundant internet connections. Same concepts apply for the SR520.

Good question if this is a supported configuration.  It looks like it could potentially cause some weirdness in parts of CCA.  I haven't personally tested it. Hopefully someone from Cisco can chime in and clarify.


Re: Dual WAN with UC540 - Best Supported Config?


So you got us thinking. The SA500 is dual wan capable. What is the typical deployment scenario you are trying to meet? Does this mean a small business will often spend the recurring charges of two ISP carriers and broadband connections? The use case of voice reliability wouldnt work on two different connections, since we only support one SIP provider or does the SP SIP provider offer this?

Also are you looking for failover or load sharing?

Steve DiStefano

Technical Solutions Architect - Partner Sales, USA

Cisco Systems

7025 Kit Creek Road

Research Triangle Park

North Carolina, 27709


sdistef@cisco. com

New Member

Re: Dual WAN with UC540 - Best Supported Config?

Hi Steve,

Internet multihoming is a very near and dear issue to me, mostly because there is not a scalable multihoming standard out there short of BGP (which is out of the cards for most of my clients).  Over the years we have always recommended T1 circuits for voice and data applications, primarily because of the SLA.  As you are aware, consumer grade broadband connections have been blowing up lately with providers offering a lot of bandwidth for next to nothing... So it is a very frequent occurrence that a client calls me and tells me their T1 at the office is painfully slow because they are used to the 20+Mb line they have at home. We are currently trying to get all of our customers onto Ethernet circuits, but in the mean time we have a problem.

So what we have been doing over the past few years is recommending to get a DSL circuit and a cable circuit in addition to the T1 and plugging them into a WAN management device to load balance all of the internet traffic. Here in South Florida AT&T and Comcast consumer grade circuits go up and down like the sun, but the chances of the T1, DSL and Cable lines all going down at the same time are pretty slim (short of a hurricane). On top of that, it also takes AT&T at least 3 months to deliver any kind of business class circuit (with an acceptable SLA).  So we also run into situations where customers need internet delivered quickly and our only option is to go with a cheap consumer grade circuit until a business class circuit can be installed.  This solution works for the folks that aren't ready to step up to an Ethernet line for their primary connectivity, but it requires that we have a device that can handle at least 3 WAN links.

I occasionally run into situations where only a failover link is required, and I always use Cisco equipment for this.  Most times I am in a situation where the customer needs to be able to load balance, failover and utilize PBR for multiple WAN links. We have been using the following device to address these issues.

I haven't tried using the SA500 device just yet. Does it satisfy the feature requirements that I need short of the number of WAN links it supports?



New Member

Re: Dual WAN with UC540 - Best Supported Config?

A couple other 3rd party solutions for dual wan is Peplink - and the Zyxel USG-100 series.

And he is right on with small businesses having an Integrated T1 from say Windstream or Cbeyond for voice and data, but with Cable broadband in our area doing 100Mb connections, people are wanting to keep the reliability of the t1 and surf on the 100Mb connection.

I would love it if the SA540 does work well, but I'm not holding my breath after all the negative stories I have read.

I will know pretty soon we are testing one in our lab in the next week.

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