Which two statements are true about best practices in VLAN design? (Choose two.) *
A.
Routing should occur at the access layer if voice VLANs are utilized. Otherwise, routing should occur at the distribution layer.
B.
Routing may be performed at all layers but is most commonly done at the core and distribution layers.
C.
Routing should not be performed between VLANs located on separate switches.
D.
VLANs should be local to a switch.
E.
VLANs should be localized to a single switch unless voice VLANs are being utilized.
Explanation:
In the distribution layer, uplinks from all access layer devices are aggregated, or come together. The distribution layer switches must be capable of processing the total volume of traffic from all the connected devices. These switches should have a port density of high-speed links to support the collection of access layer switches. VLANs and broadcast domains converge at the distribution layer, requiring routing, filtering, and security. The switches at this layer must be capable of performing multilayer switching with high throughput. Only certain Catalyst switch models can provide multilayer switching; be sure to understand which ones can do this.
A switched environment offers the technology to overcome flat network limitations. Switched networks can be subdivided into VLANs. By definition, a VLAN is a single broadcast domain. All devices connected to the VLAN receive broadcasts from other VLAN members. However, devices connected to a different VLAN will not receive those same broadcasts. (Naturally, VLAN members also receive unicast packets directed toward them from other VLAN members.)
A VLAN consists of defined members communicating as a logical network segment. In contrast, a physical segment consists of devices that must be connected to a physical cable segment. A VLAN can have connected members located anywhere in the campus network, as long as VLAN connectivity is provided between all members. Layer 2 switches are configured with a VLAN mapping and provide the logical connectivity between the VLAN members.