Replication problems

Hello,
We have problems with a SQL replication between 2 SQL Servers, some days it
works fine, but some times the replication is not succeed and there are lots
of missing records.
We do not know how to determinate what is causing these problems, and we
would like to know if there is a tool or application to monitor the replica
and to notify us when the problem occurs and what is causing it.
The replication between the 2 SQL servers is made through a dedicated link
of 128 Kbps and when the replication fails the link is saturated. Is there
any way to compress the replication data before it is transmitted through
our dedicated link?
Thanks in advanced for your help
The main tools to monitor replication are Replication monitor, Performance
Monitor and Profiler, but sometimes examining the system tables can help
determine the source of the problem.
Firstly what type of replication are you using?
Are you seeing any reported errors and if merge, are you seeing any
conflicts?
Are the records missing from the subscriber after being added on the
publisher or vice-versa, or inserted records on the subscriber are being
removed?
Are you using filters?
Are you doing bulk-inserts?
There are various posibilities but if you can answer the above questions
I'll be better placed to try to answer.
Regards,
Paul Ibison