Slow speeds after Vonage install?? Help..

Posts: 1 · New Forum Member Joined: Jul 22, 2006 Posts: 1

I have a Surfboard SB5101 cable modem and Motorola VT2442-VD. Phone works fine but the bandwidth went from 2.5-3mb to 0.5 to 1mb. Is there anything I can do? Thanks.

Posts: 4777 · Vonage Forum **MVM** Joined: Aug 30, 2005 Posts: 4777

Please post the technical details listed in the sticky message at the top of the forum. Since your issue appears to involve the VT2442, please run the forum Voip test with and without the VT2442 in the setup,. and post the detailed results of both.

Posts: 1179 · Member of the Week Joined: Feb 28, 2005 Posts: 1179

Buzzz, how old is your computer Network Interface Card? If it is old, then it's a communication issue and you will need to manually set the speed so that it can communicate without issue. I had a similar problem with my NIC b/c it was so old (i.e. more than 3 yrs old). In my case, I have one that is 7 yrs old and so it cannot auto-negotiate the speed with the router.

let me know if this applies.

Posts: 72 · Full Forum Member Joined: Jun 15, 2006 Posts: 72

mundy5 wrote:

have one that is 7 yrs old and so it cannot auto-negotiate the speed with the router.

If it can't negotiate the speed and they end up with different speeds, it just won't work at all. The problem is with negotiating the duplex. If one side is set to full and the other to half, it will work but not very well. There will be many errors and collisions that cause lost data that must be retransmitted.

Posts: 1179 · Member of the Week Joined: Feb 28, 2005 Posts: 1179

Maestro wrote:

If it can't negotiate the speed and they end up with different speeds, it just won't work at all. The problem is with negotiating the duplex. If one side is set to full and the other to half, it will work but not very well. There will be many errors and collisions that cause lost data that must be retransmitted.

Not so. Mine is running 10mbps full duplex. it's the auto negotiating problem. i had to manually set it 10mbps full duplex and it works great. When I had it set to auto, it would fluctuate from working normally to working slower than dialup.

Posts: 72 · Full Forum Member Joined: Jun 15, 2006 Posts: 72

mundy5 wrote:

[Not so. Mine is running 10mbps full duplex. it's the auto negotiating problem. i had to manually set it 10mbps full duplex and it works great. When I had it set to auto, it would fluctuate from working normally to working slower than dialup.

Correct. The side that can negotiate figured out the speed of the other side so that the link worked. It couldn't figure out the duplex so it ended up not matching which is what caused the problems.

If one side is set to 10 Mbps and the other is set to 100 Mbps, the link will just not work at all.

This is what Cisco has to say about it:

When to Use Ethernet 10/100 Mb Auto-Negotiation

Auto-negotiation is an optional function of the IEEE 802.3u Fast Ethernet standard that enables devices to automatically exchange information over a link about speed and duplex abilities.

Auto-negotiation is targeted at ports. These ports are allocated to areas where transient users or devices connect to a network. For example, many companies provide shared offices or cubes for Account Managers and System Engineers to use when they are in the office. Each office or cube has an Ethernet port permanently connected to the office network. Because it might not be possible to ensure that every user has either a 10 Mb, a 100 Mb Ethernet, or a 10/100 Mb card in their laptop, the switch ports that handle these connections must be able to negotiate their speed and duplex mode. The alternative is to provide both a 10 Mb and a 100 Mb port in each office, or cube and label them accordingly.

One of the most common causes of performance issues on 10/100 Mb Ethernet links occurs when one port on the link operates at half-duplex while the other port operates at full-duplex. This occurs when one or both ports on a link are reset and the auto-negotiation process does not result in both link partners having the same configuration. It also can occur when users reconfigure one side of a link and forget to reconfigure the other side. Both sides of a link should have auto-negotiation on, or both sides should have it off. Cisco recommends to leave auto-negotiation on for those devices compliant with 802.3u.

Many performance-related support calls are avoided if you correctly configure auto-negotiation. Many Catalyst Ethernet switching modules support 10/100 Mb and half-duplex or full-duplex. Exceptions include the Ethernet Group switch modules. The show port capabilities {mod_num} | {mod_num/port_num} command shows if the module you are working on supports 10/100 Mb and half-duplex or full-duplex. This document uses two WS-X5530 Supervisor Engine IIIs, each with two optional uplink 10/100 BaseTX Ethernet ports installed.