Problem in network

[rahilkhan]

Dear experts hi,

I am working with my customer to resolve the problem of slow internet access. Customer's network is too old to manage. Network comprise of :

Core Switch : 3com 4007 CB9000

Access Layer switchs: 3com 1100 and 3300.

On edge side cisco asa 5520 firewall is deployed. 1Gbps broadband internet LL is directly connected to cisco asa 5520.

connectivity is like this:

Internet LL------ofc-------- cisco asa firewall--------------3com 4007--------------access layer switches(3com 1100 and 3300).

I am not able to find out where is the root cause. Kindly help it is urgent.