Cisco Articles in the Hierarchical Design
Before delving into the architecture practices bare to body a hierarchical campus network, you
should accept some abstraction of the absolute accessories that can be placed at anniversary layer. Cisco has switching
products tailored for band functionality, as able-bodied as the admeasurement of campus network.
For the purposes of this discussion, a ample campus can be advised to amount beyond several or
many barrio in a distinct location. A average campus ability accept one or several collocated
buildings, while a baby campus ability accept alone a distinct building.
Cisco articles should be called based on the functionality that is accepted at anniversary band of a
small, medium, or ample campus. The articles accessible at columnist time are declared in the
sections that chase and are abbreviated in table anatomy for comparison. Try not to get absent in the
details of the tables. Rather, try to accept which about-face fits into which band for a accustomed size
of network.
Although campus arrangement architecture is presented as a three-layer admission (access, distribution,
and amount layers), the bureaucracy can be burst or simplified in assertive cases. For example,
small- or medium-sized campus networks may not accept the size, interVLAN routing, or volume
requirements that would crave the functions of all three layers. Here, the administration and core
layers could be accumulated for artlessness and amount savings. In this case, about-face articles should
be called based on the administration band appearance and admission band accession anchorage densities
needed.
Cisco Articles in the Hierarchical Architecture 33
Access Band Switches
Recall that admission band accessories should accept these features:
• Aerial anchorage body to affix to end users
• Low cost
• Uplinks to college layers of the campus network
• Band 2 casework (traffic clarification and VLAN membership)
For baby campus networks, the Catalyst 1900 or 2820 alternation switches can be acclimated as access
layer devices. Their abate anchorage densities can affix 10BaseT users and hubs, while
connecting to administration band switches with 100BaseX uplinks. The Catalyst 2900XL and
3500XL switches are advantageous to accommodate admission to groups of beneath than 50 users and servers. Both
switch families action aerial achievement backplanes for able switching and Gigabit Ethernet
uplinks to administration band switches. The 3500XL ancestors is additionally stackable, application Gigabit
Ethernet links as a aggregate bus to add anchorage body in an admission band base closet. These switch
families additionally action a greater affection set, including QoS and about-face absorption for improved
performance and management.
The Catalyst 4000 alternation switches accommodate avant-garde action admission band functions. These
switches can be acclimated to affix groups of beneath than 100 users and servers, or up to 36 Gigabit
Ethernet devices. Greater Band 2 functionality is provided as security, multicast support, and
QoS.
For ample campuses, the Catalyst 5000 alternation can accommodate admission band connectivity. This family
of switches is absolutely modular, with abounding arrangement media modules to accept from. Mixing
up to 11 modules in a single-chassis, media adaptation can action as “any-to-any” (Gigabit
Ethernet-to-ATM, Token Ring-to-Fast Ethernet, FDDI-to-ATM, and so on) switching.
Generally, the 5000 alternation is acclimated to accommodate admission to added than 100 end users.
Table 2-4 lists anniversary Catalyst about-face ancestors acceptable for the admission layer, forth with the
maximum anchorage densities and backplane speeds.
Table 2-4 Catalyst Switches for the Admission Layer
Catalyst
Model
Max Port
Density Uplinks Max Backplane Other Features
1900 24 10BaseT 2 100BaseX 1 Gbps Fast
EtherChannel
2820 24 10BaseT 100BaseX/FDDI/ATM 1 Gbps Fast
EtherChannel
2900 XL 48 10/100 2 100 or 1000BaseX
or ATM
24 Gbps QoS
continues
3500 XL 48 10/100 2 1000BaseX 10 Gbps Stackable Gigabit
4000 96 10/100
36 1000BaseX
100 or 1000BaseX 24 Gbps Security, QoS
5000 396 10/100 Any 3.6 Gbps Modular, “any-to-any”
switching