WAN router LAN interface Best practice for speed

[Steve Coady]

Hello

I have an ASR router with a WAN link of 100M.

The LAN connection for this router is Gig capable.

Should I configure the LAN interface on the router for Gig or would this cause problems with potentially 10 times the data

exiting the LAN out to the WAN with only a 100M pipe?

[Joseph W. Doherty · Accepted solution]

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Posting

If you set your LAN interface to run at 100Mbps, likely you would just be moving your possible bottleneck one hop deeper into your LAN (often on devices with weak QoS support).

Leave your LAN interface at gig.  If congestion, on WAN egress, becomes an issue, you can then try QoS to mitigate it.  For example, for starters, you might want to place your WAN egress traffic into fair-queue.