Is continual cable modem transmission activity normal (with no devices connected)?

[velocite]

My setup:
I have cable broadband and cable telephone (but not cable TV) .
A Virgin Media supplied Ambit 256 cable modem is connected to the WAN port of a D-Link DIR-100 wired router. My Internet connection is good – achieving a solid 2080Kbps download and 245Kbps upload.

However the modem appears to be constantly transmitting – the ‘send’ and ‘enet’ lights are very active, even when no computers are connected to the router.
If I switch off the router, or disconnect the Ethernet cable between the modem and router, the ‘enet’ light on the modem obviously goes out; however the modem’s ‘send’ light keeps going.
Is this normal? (perhaps a heartbeat sent both up the broadband cable and also to the downstream Ethernet side?)

[Kymmy]

There should always be some connectivity but it shouldn't be constant. Mine flashes about every second when everything else is idle.

In the end if your speed is what you wanted and you;re happy then don;t worry about it.

Kymmy

Originally Posted by velocite

My setup:
I have cable broadband and cable telephone (but not cable TV) .
A Virgin Media supplied Ambit 256 cable modem is connected to the WAN port of a D-Link DIR-100 wired router. My Internet connection is good – achieving a solid 2080Kbps download and 245Kbps upload.

However the modem appears to be constantly transmitting – the ‘send’ and ‘enet’ lights are very active, even when no computers are connected to the router.
If I switch off the router, or disconnect the Ethernet cable between the modem and router, the ‘enet’ light on the modem obviously goes out; however the modem’s ‘send’ light keeps going.
Is this normal? (perhaps a heartbeat sent both up the broadband cable and also to the downstream Ethernet side?)

As with all modems it has the capability to talk back and forward to the Network, all it is doing is letting the Network know its still there by sending small amounts of data back to the Virgin servers.

[velocite]

When idle, I'm seeing about 8-10 flickers of the 'send' and 'enet' lights per second (or 8-10 flickers of just the 'send' light, if I disconnect my router from the modem's 'enet' port).
Do other VM users see just a single flash every second or so?