Superhub : Superhub & Virgin Media Business

[APS]

Originally Posted by itcomms

are you getting any errors in the logs?

why such a drop in MTU Size? surely this can cause issues with networks sending packets larger then your MTU?

On our router when you reduce the MTU size, there is also an option (we have checked) for the router to fragment packets larger than this size going from LAN to WAN.

I believe though that during initialisation of a TCP session between a device and a router, it will say what its maximum MTU size is and the device connecting to it should limit its packet size accordingly.

[MovedGoalPosts]

Originally Posted by itcomms

Rob, do you not have any mail servers?

Not on site no. We migrated to the cloud about a year ago, and our user's simply connect to the interweb servers via their locally run Outlook. We'd had too many issues with local server and connection downtime, plus issues with smartphone use that the cloud made sense especially when you could so easily log in from any remote location even if our own stuff was a problem. The cloud system also removes a big headache of local backups.

We don't do much remote or home working, but for those that do I am able to congure our network to give remote login to file shares on the server. The ADSL has static IPs, so dynamic IP on the cable isn't really an issue, especially since they are so sticky.

We do have some 20 users, and internet activity is critical to the business. Originally the VM cable was put in as a backup to the ADSL. Now it's reversing as Cable is offering the faster, more stable speeds than ADSL.

[itcomms]

are you getting any errors in the logs?

Originally Posted by ccarmock

I see VM decided to shut the thread down on the community forum about this.

However I just wanted to post here (as I can't there!) that changing the config of the Cisco router I have behind the Business Superhub with ip mtu 1460 on the WAN interface and ip tcp adjust-mss 1420 on the internal VLAN1 interface seems to have fixed the email delay problems I had been experiencing.

[ccarmock]

No I am not seeing errors in the logs at all now. The Superhub is just reporting some T3 timeouts as I am in a heavily congested area, but that's another story.

I am not seeing errors in the Cisco router logs either, and the errors I was seeing in the SMTP Receive log on Exchange have gone away now too. Email is being delivered quickly.

So MTU of 1460 has really helped for me. As soon as new Business Superhub firmware is available I will try to revert to default settings, but right now this has resolved my immediate issues.

Now just to have the IP Edge network team address my congestion issues! I have had a week of 'no ETA' Today I escalated to the CEO's office and am told that they put a planner on it today, planning should be complete by tomorrow lunchtime and they are working to implement by Friday if all goes well.

Now this leads me onto a further issue with the business superhub. At times congestion is so bad I am getting 100% packet loss. When this happens the upper blue light on the Superhub stops flashing and goes solid blue. If it stays in this state too long sometimes the superhub will not recover and needs a restart in order to work again.

[itcomms]

i'm going to Order a Draytek 3200N Quad Wan Port Router and get Virgin to put us back on 50Mb and test again as the bandwidth of the 10Mb service is causing us issues.

Questions
1. Ask Virgin Meida for a block of 5 IPs?
2. Setup the Draytek router and set MTU to 1460
3. Do we need to change MTU on the Servers?

is there anything else i need to be aware of?

[ccarmock]

I still have the MTU size set on the Exchange server too, but will text with that back at the default and just MTU changed on the router and let you know how I get on.

[itcomms]

Draytek Vigor 3200n Quad-WAN Router now ordered

currently running the Linksys E1000 Router with the Cisco 2100 Modem.

can't see the MTU setting within the E1000 router to "Accept large incoming fragmented UDP or ICMP packets"

think this option is only available on the Draytek.

Originally Posted by ccarmock

I still have the MTU size set on the Exchange server too, but will text with that back at the default and just MTU changed on the router and let you know how I get on.

so you suggesting setting the MTU to 1420 on the router?

[APS]

On our router we only had the option to change the MTU size. I believe any device connected should be able to work out the MSS size from the MTU size although there is a specific setting for the CISCO routers I believe relating to packets they reform.

We did not change anything in our Exchange server - I am hoping/believe it should work out what size of packet to use when it negotiates the connection to the gateway (the router). Email is passing through OK now.

For those hoping this particular issue may be solved by a firmware upgrade - it seems unlikely as having done a little more reading it seems to be a feature of running an L2TP tunnel. See this article here: http://www.cisco.com/en/US/tech/tk80...80094c4f.shtml

There are other issues to be fixed though like some VOIP issues and apparently the tunnel going down occasionally and taking a while to restart (to quote the VM tech support guy).

[itcomms]

so even fixing the MTU size, we will still have issues with VoIP??

[APS]

We do not use VOIP, but earlier in this thread someone seemed to have been given information that any VOIP issues might be limited to running the modem in NAT mode.

Some advice was given to go for the subnet of fixed IP addresses which avoids using NAT. ccarmock said he had been running for 39 days without issue in that mode.

[ccarmock]

I am suffering no VoIP issues (apart from when congestion strikes) as APS says. I have the 6 IP routable subnet.

[itcomms]

just spoken to VM about going back to 50MB and use the work around.

Been told that VM are no longer doing 50MB until the issues have been fixed.

NO ETA

[ccarmock]

I had also heard they were suspending new sales of the 30 Mb/s and 50 Mb/s service pending new Superhub firmware. You might be able to make a case to go back to the 50 Mb/s service with the knowledge of the issues, as you had already had that service and rolled back. Ie you're not strictly speaking a new 50 Mb/s customer.

[qasdfdsaq]

Oh wow, admitting a problem and doing something sensible about it. Impressive.

[Sephiroth]

More like the Super Hub strikes again.