What is the meaning of traffic segmentation?

Question

Cisco

It was possible to look at the network of one of the providers. They have traffic segmentation configured on all switches (traffic from all ports is allowed only to uplink, from uplink to all ports), thus traffic between subscribers is directly prohibited.
A tsiska is installed in the provider's server room, which is engaged in traffic aggregation (local proxy arp is configured on it).
What is the point of driving traffic through a piece of iron specially installed for this? Perhaps this will help against the left dhcp (we put our dhcp as close to the cisco as possible, and ideally we connect it to it - as a result, our dhcp will theoretically be the fastest). What else could make sense?

Answer 1

What is the meaning of traffic segmentation?

Reducing the size (number of devices) of the L2 domain, which leads to greater stability (including less intensity of broadcast and multicast traffic, as already mentioned)

What is the point of driving traffic through a piece of iron specially installed for this?

If the main service is Internet access, then the traffic mostly passes through some central device anyway, that is, roughly speaking, we get benefits without a negative impact on the provision of the service.