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Arris SB8200 LAG capability on DOCSIS 3.1 and 1gbit plan

Regular Visitor

Arris SB8200 LAG capability on DOCSIS 3.1 and 1gbit plan

The Arris SB8200 has 2 gbit ethernet ports which allegedly are there to support link bonding on the downlink to your home network.  Two years ago an Arris employee suggested that this capability "should be coming soon".  I'd be interested in setting this up to provide for link resiliency and any possibility that Comcast might offer a tier above 1gbit, or if boost/blast/whatever allows bursting above 1gbit.

 

From how I'm parsing that thread, two years ago Comcast disallowed this feature in the configuration profile being provisioned to the modem.  Has the situation w/r/t these ports being allowed to form a LAG changed?  Is there any point in me testing this?

Expert

Re: Arris SB8200 LAG capability on DOCSIS 3.1 and 1gbit plan

Comcast does not yet offer speeds above 1 gig on DOCSIS. There would be no speed advantage to using LAG at this time. Unless you are talking about getting a second IP address to enable the second port to be used as another internet connection ?

 

 



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Regular Visitor

Re: Arris SB8200 LAG capability on DOCSIS 3.1 and 1gbit plan


@EG wrote:

Comcast does not yet offer speeds above 1 gig on DOCSIS.


Thirdy-party reports suggest the 1gbit tier is provisioned at 1.2gbit.  This aligns with my previous experience where Extreme 250 would regularly run @ 300mbit.

 


@EG wrote:

There would be no speed advantage to using LAG at this time. Unless you are talking about getting a second IP address to enable the second port to be used as another internet connection ?


I'm looking to accomplish two things with a LAG.  One, provide for link redundancy in the event of a cable or port failure.  Two, allow for > 1gbit throughput when utilizing multiple traffic streams on a single IP.  

 

The LAG configuration option did not appear until a firmware update was pushed by Comcast in February of this year.  Some users are reporting it causes issues for them, and another firmware was apparently pushed in May.  As nobody seems to offer changelogs it's anyone's guess what was included in these updates.

Regular Visitor

Re: Arris SB8200 LAG capability on DOCSIS 3.1 and 1gbit plan

I've successfully established an LACP bond on this device, but unfortunately it's to a router that will only let me establish an LACP bond on two interfaces, so I don't yet have a way to test the results back to a connected client PC (I can bond 2 links to the modem, or back into my network - but not both - meaning I'm stuck at 1gbit no matter what).  I have a 10gbit solution coming in a few days and will be able to test this a bit more robustly.

 

Here is the guide from Arris on the LACP configuration they are expecting (which is technically non-compliant due to layer 3+4 hashing but whatever).

Regular Visitor

Re: Arris SB8200 LAG capability on DOCSIS 3.1 and 1gbit plan

Getting closer:  https://i.imgur.com/tvybovW.png

 

Here we have two bonded 1gbit interfaces (ether9 and ether10) each dividing the bandwidth and sending down the 10gbit interface sfp-sfpplus1.   While we're not going north of 1gbit in this test, it does demonstrate that the modem is at least able to successfully negotiate an active LACP connection to the router and can spread the load across the available links.

Regular Visitor

Re: Arris SB8200 LAG capability on DOCSIS 3.1 and 1gbit plan

^ I feel like you're not reading this thread, but thanks for the input I guess 

Regular Visitor

Re: Arris SB8200 LAG capability on DOCSIS 3.1 and 1gbit plan

Sadly, I'm now seeing the behavior others have reported - when enabling LAG on this modem, the device now likes to reboot approximately once a day for reasons that aren't clear.  Looks like this feature still isn't quite cooked yet...

New Poster

Re: Arris SB8200 LAG capability on DOCSIS 3.1 and 1gbit plan

My internet speed was lower using LAG with the newest firmware on R7900P router.
Regular Visitor

Re: Arris SB8200 LAG capability on DOCSIS 3.1 and 1gbit plan


@Eolas wrote:
My internet speed was lower using LAG with the newest firmware on R7900P router.

My speed tests are roughly equivalent with bonding enabled vs disabled.  Is it possible that enabling LACP on the R7900P disables some hardware acceleration or otherwise impacts CPU such that the router isn't passing packets as fast as it does w/ LACP disabled?

Regular Contributor

Re: Arris SB8200 LAG capability on DOCSIS 3.1 and 1gbit plan

I have LAG enabled on my SB8200 to an Asus RT-AC88U. I also have LAG on the router’s LAN ports Eth1 and Eth2 to a managed switch.
I can confirm that I do indeed get up to 1.2Gbs with 2 ports on the SB8200 vs 0.98Gbps with 1.
I say up to, because during prime time in the evening I don’t usually get more than 800kbs or so but other times per day or night it’s 1.2.

So indeed port bonding does increase throughput and take advantage of over-provisioning but the gain isn’t worth fussing or spending money on acquiring.
But if your router supports it, it seems to work fine.
I haven’t noticed regular reboots yet.

There is no difference when using a single 1Gbps ethernet connected device. Just almost 1Gbps either way.