SCE is a very comprehensive SP solution and even tough it is more tailored towards web filtering and bandwidth control it definitely has many anti-spam features, please check the following link:
We have also seen many SPs use bandwidth and network control solutions from Opnet and Sandvine.
The opnet solution is spefiically designed for ISPs and supports multi-tenancy.
Regards
Farrukh
Getting Started
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: