Chris Stone
Global Product Line Director

Don’t Get Caught Flapping


During the last week, has your router reloaded, gone down, or had BGP problems?  Over the last several days, the internet routing table BGP (Border Gateway Protocol) has grown to over 512,000 routes and some routers (even high-end routers) don't have sufficient memory to handle a full table.

Check out the BGP Entries below. When a router is exhibiting these issues it's known as "flapping." Briefly, BGP is the routing protocol used to share the master routes of the internet (it's the map of the internet).

"Flapping" affects all OEM routers that are WAN-edge facing and are doing BGP.  For example, Cisco-specific units such as the Cisco7206VXR, Cisco3900, Catalyst 6500 and Cisco 7600 series could be affected. Luckily, there are workarounds and solutions for this issue that we would like to share.

The first solution is to buy additional memory to support the route table. As one IT manager says, "you should max out any router that is doing BGP with the full routing table" to give you long term support of the ever-growing routing table.

Another solution is to buy a router and memory that supports the number of routes you need. For example, the ASR1000 series supports 4, 8, and 16GB of DRAM. Click here for some additional workarounds for Cisco routers.

To that end, the internet routing table will continue to grow. Who knows where it will end? With that in mind, keep an eye on that routing table and don't get caught flapping! 

ACTIVE BGP ENTRIES = 525,321 and counting


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