Cisco WS-C3750-48PS-S Software Configuration Manual page 59

Chapter 1 Overview
Network Configuration Examples
In the wiring closet, each switch stack has IGMP snooping enabled to efficiently forward multimedia
and multicast traffic. QoS ACLs that either drop or mark nonconforming traffic based on bandwidth
limits are also configured on each switch stack. VLAN maps provide intra-VLAN security and prevent
unauthorized users from accessing critical pieces of the network. QoS features can limit bandwidth on
a per-port or per-user basis. The switch ports are configured as either trusted or untrusted. You can
configure a trusted port to trust the CoS value, the DSCP value, or the IP precedence. If you configure
the port as untrusted, you can use an ACL to mark the frame in accordance with the network policy.
Each switch stack provides inter-VLAN routing. They provide proxy ARP services to get IP and MAC
address mapping, thereby removing this task from the routers and decreasing this type of traffic on the
WAN links. These switch stacks also have redundant uplink connections to the backbone switches, with
each uplink port configured as a trusted routed uplink to provide faster convergence in case of an uplink
failure.
The routers and backbone switches have HSRP enabled for load balancing and redundant connectivity
to guarantee mission-critical traffic.
Catalyst 3750 Switch Software Configuration Guide
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