IBM Nortel Networks L2/3, Manual

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108
Nortel Networks L2/3 Ethernet Switch Module for IBM
Eserver
BladeCenter
!
interface Vlan10
ip address 172.16.10.10 255.255.255.0
!
ip classless
ip http server
ip http secure-server
!
control-plane
!
line con 0
line vty 0 4
password c
login
line vty 5 15
no login
!
end
7.8 Layer 3 topology sample configurations
The configuration samples in this section use Layer 3 switching (routing) in addition to Layer
2 switching (bridging, forwarding). They are based on the simple configuration that was
introduced in 7.6, “Basic Layer 2 entry topology” on page 69.
Implications of using Layer 3
These Layer 3 configurations are different from the Layer 2 configurations in the following
ways:
򐂰 802.1q trunking is not required on the connections to the Core switches. Traffic from the
VLANs used for the server blades (VLAN 10, VLAN 20) is sent on the uplink trunks as
routed traffic and identified by its source and destination IP addresses. There is no need to
identify its VLAN association.
򐂰 Additional VLANs and associated subnets are required for the connections to the Core
switches. The uplink connections do not share the VLANs (10, 20) or subnets (10.10.x.x,
10.20.x.x) used for the blade servers. In some of the examples that follow only VLANs 35
and 46 are used. The VLANs and subnets used are:
– VLAN 35: 10.35.x.x, used to connect GbESM 1 to upstream routers
– VLAN 36: 10.36.x.x, used to connect GbESM 1 to upstream router Core2
– VLAN 45: 10.45.x.x, used to connect GbESM 2 to upstream router Core1
– VLAN 46: 10.46.x.x, used to connect GbESM 2 to upstream routers
򐂰 Upstream routers must be able to find the route to the blade servers. This requires either
the use of explicitly configured (static) routes or the use of a dynamic routing protocol.
Dynamic routing protocols enable routers to share route information with their neighbors.
Examples of the use of static and dynamic routing are included in this section.
򐂰 High Availability designs using Layer 3 require different techniques than those using solely
Layer 2. Examples of HA designs are included in this section.