What is the network structure in large companies?

Question

Computer networks

I'm wondering what software or equipment is used as a proxy\firewall in large companies (500+ people). There should also be admins from very large companies, tell us how Internet access is implemented in such companies) Or maybe there are even network diagrams with the names of equipment and software.
PS. I don’t need to make such a network, I’m only interested in self-development!

Answer 1

So right here they laid out schemes of corporate networks for you) As an ISA proxy, as Cisco ASA firewalls, as switches in the Nexus data center. Reserves via STP/HSRP/Is-Is. The number of the company ~ 2k people in one branch.

Answer 2

Yes, actually it all depends on the company, tasks and curvature / laziness / knowledge of the administrator. Variations on the theme WAGON!!!
On the gate, as a rule, they put something smarter: Kerio, Forefront. It is possible in principle and linux. Depends on the skills of the administrator and the need to filter traffic.
The kernel is some CISCO/Juniper/Mikrotik thread (by the way, I worked with the latter option).
End routers - something normal with VLAN support, because without it there is nowhere. For example HP Procurve.
Actually, at some point, everything rests simply on the performance of one gateway / mail, etc., and they have to be "clustered".
By and large (well, conditionally), in addition to a competent breakdown into VLANs and high-quality equipment, the differences between large networks and not large ones are not very big. I'm not talking about provider networks for thousands of users.

Answer 3

The company of the company is different, a large ISP is one structure, a large DC is another, a large hosting is the third, a large mobile operator is the fourth, a large collective farm "Krasnaya Zvezda" is the fifth, a large broker is the sixth, you at least specify what direction this company is, solutions and requirements for implementation can be up to the opposite. Proxies are rarely used in large companies, especially if the traffic is large enough, because maintenance is hemorrhoids, they put full-fledged managed routers behind perimeter protection.