Other Line Options
This shows your line rate:
Changing the Line Rate
This sets the line rate on your line:
- Available on BT 21CN ADSL
These stability options refer to how aggressive BT's DLM is when monitoring and managing the line.
Usually we would suggest keeping it on Normal (the default). Using increased stability options increases DLM sensitivity, so can have the side effect of making your line sync at lower speeds.
Other Line Options
Most of these options are available on all lines:
Forces an MTU regardless of what is negotiated by your router.
More Info: MTU is negotiated upon connection. We usually like 1500 MTU, however, there can be situations where forcing 1492 MTU is required. For example, if your router negotiated 1500 MTU initially but you make a connection to a server that wants to re-negotiate a lower MTU it will try to do this using ICMP, but if your router has a misconfigured firewall that blocks ICMP this can't be renegotiated and the connection to the server will have problems. This is seen when connecting to certain web sites, bank web sites and https sites. Forcing 1492 MTU from the start means that all your traffic is in packets of 1492 bytes and so won't have this problem.
More Info: During the PPP connection when your router initially syncs up and logs in to us, the PPP connection is passed via BT. Sometimes BT can change the MTU. With this option we will accept the PPP connection from BT, but will then renegotiate the PPP connection with your router allowing the MTU to be reduced. On TalkTalk connections the MTU is always negotiated as 1492 MTU, you will need to select LCPFix and 1500 MTU to fix this, otherwise the LNS will use 1492 MTU when renegotiating. This is sometimes called 'LCP re-negotiation always'
More Info: LCP echoes usually stop responding if the line has gone down. Our LCP monitoring, which produces the graphs, will drop the line if there are no replies after 60 seconds. When bonding or used in a fall-back setup, having a faster timeout is useful in order to fall-back quicker.
From time to time there are upgrades to the LNSs. This is usually to add new features, or fix bugs.
Upgrading an LNS is very quick, and it is only off line for under a second. However, it does mean stopping all of the sessions on the LNS, which means we will force your DSL service to reconnect. You can set the preferred time for the reconnect to happen, the default is 1AM.
We have more info here: LNS Switches