Cisco 877 not getting full ADSL speed?

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<shrug> Then use the Netgear. Not sure why they're different... they just are. Perhaps the Netgear handles encryption and collision avoidance better. Perhaps the Netgear isn't doing as much "other stuff" behind the scenes; this is similar thinking as to why L2 switches handle more throughput than routers... sure, routers can route, but it comes at a performance cost. Switches aren't busy doing all that L3 stuff, so they can just focus on pushing bits.

I'm not saying that the Netgear doesn't route... I'm simply saying that the Netgear probably isn't doing things that the Cisco router is.

 

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Hey there phatboy, if you are still around (if not, anyone else who could help), could you post your config here for the router which had the issue, i.e, the config after your speed issue was solved.

I am having the exact same issue on a cisco router 877 (not W). For a 4MB DSL connection, speedtest results do not show the desired "full speed" and there is comparatively a small delay for webpages to open up on connected PCs.

Here is my running config file: View attachment 2573

Could you please tell me what is wrong with my config?

Thanks in advance!

 

I did find on my 877-M that it had issues syncing at a higher speed due to the V4 DSL Firmware. Downgrading the firmware to a version that had V3 inside it fixed the throughput issues for me

So i would try downgrading to an earlier version of IOS, clean slate the router and start again

That's what I did

 

Hi Tim,

It sounds like a strange case, however maybe I can shed some light on why you are seeing the difference with the netgear and cisco router.

I used to work for an ISP and we would see this issue quite often, like a few others have said the more bare essential a router the faster speed you seem to get. There is no doubt that the Cisco router is better in terms of functionality that the netgear, however the speed difference is more likely to do with the extra processes the Cisco router is functioning. Even though your CPU stats look great, it is very similar to how a firewall works.

For example in my home network I currently run VDSL on FTTC and used to achieve 54Mbps, now I have a Juniper 5GT firewall doing the PPPoE I get approx 48 - 49Mbps. Yes I am on the latest firmware and nothing has changed in terms of setup, however since the terminating device is a firewall it is running stateful packet inspection on all traffic that comes in from the WAN to the LAN and back again.

Similar to your Cisco router I believe you have a similar problem whereby the extra functionality isn't tuned Cisco side to handle the quicker speeds.

Things I would advoid, chopping and changing routers to test the speed of your connection. If you are on BT based ADSL you will be subject to Dynamic Line Management throttling upon several disconnections.

Try testing your IP profile, I have seen cases where the syncrate is still good from the router to the exchange however the actual speeds are not materialising. I don't know your provider or how you can check (with me I log into my ISP portal and check the connection settings). However if you are say syncing at 20Mbps to the exchange with Cisco but only getting say 14Mbps, this is probably a stuck BRAS profile. Again this is dynamically assigned and increases automatically with stability, this can be manually set by your ISP.

To check the syncrate against your line speed profile run a test at: BTW Performance Test

This will tell you if you are reaching an acceptable speed for your syncrate.

Hopefully this helps you clarify if the Cisco router is causing problems on the WAN side.