Choosing a Branch Router – What Cisco Won’t Tell You

Q: These are deployed as branch routers.  What are common WAN speeds in a modern branch office?

A: The average WAN performance for the US in 2015 was a mere 50Mbps¹.  While much higher speeds – 10Gbps is now readily available to businesses in major metro areas – are available for environments that demand it, such as datacenters or headquarters offices, the majority of sites will have limited WAN needs, and will fall around this 50Mbps average.

Q: What criteria should an organization use when determining what branch router to deploy?

A: First of all, performance is the main criteria – if the router can’t physically handle the connection, then there isn’t any point to considering it.

Beyond this, we look at interface needs and interoperability concerns.  For example, if the router needs 4G/LTE connectivity, then the ISR G2 is the minimum router to use, as that’s where the first 4G interface cards are introduced.  As for interoperability, some environments, especially where Cisco voice products are in use, require specific router families or software versions to ensure that all components of the IT infrastructure operate in harmony.

Finally, we look at what features we need to deploy on the routers.  As Cisco’s branch router families have evolved, so have the software features on these routers.  Looking at what the business needs are for the WAN environment will steer us to certain feature needs, which will then dictate what router families are best suited for your environment.

Q: The ISR 4000 routers promise a major performance improvement as well as a host of new features.  I can even run a Linux container or VM on one.  Why shouldn’t I upgrade right now?

A: There are a number of reasons to avoid or postpone an upgrade to the ISR 4000.

First of all, it comes down to if it’s even needed.  Without an increase in WAN performance, the ISR 4000 won’t actually contribute anything else unless the existing router is underpowered.  Even if the WAN connection is upgraded as well, if the existing WAN connection isn’t being regularly saturated, the end users won’t see any performance improvements.

Second is the newness of the ISR 4000 platform.  As a much newer platform that’s undergoing rapid software development, software defects are a fact of life.  A great deal of effort is expended by every IT organization in troubleshooting, identifying, and remediating software defects across all components of the IT infrastructure.  Why create needless work in this area?

Finally, consider the labor and disruption involved in changing out branch office routers.  Configurations need to be converted and vetted for proper operation on the new hardware, IT staff or 3rd party labor needs to be deployed to each site, and maintenance windows and rollback strategies need to be created.  With the importance of networking to modern business, change isn’t done lightly anymore.

Q: The ISR G1 routers are no longer supported by Cisco.  Why should they be considered at all for use in an enterprise environment?

A: The ISR G1, from a performance, featureset and reliability perspective, is still a relevant product, and can serve well in existing environments for some time to come.  Because of this, third party maintenance is an established option in the marketplace to extend the lifecycle of these routers.  Consider exploring this option to keep working hardware in service and postpone a major hardware upgrade until it is truly necessary.