IBM 8285 Nways, Installation And User Manual

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Linking Subnetworks to Form a Campus Network
An ATM Campus Network is a group of ATM subnetworks connected by NNI trunks. Each NNI trunk
connects the ‘boundary switch’ in one subnetwork to the boundary switch in another subnetwork, as
shown in Figure 19.
Figure 19. NNI Trunks Between Subnetworks
Configuring NNI Trunks Between Subnetworks: On each of the boundary switches that will be linked
by an NNI trunk, you will:
Ÿ Configure the port for the trunk as an NNI port (using the SET PORT command)
Ÿ Define a ‘static route’ (using SET STATIC_ROUTE ) that associates a local cluster number (ACN) with the
address of the remote boundary switch
Ÿ Configure a ‘logical link’ to the local ACN associated with the remote switch (using SET
LOGICAL_LINK )
You can configure multiple logical links over the same physical port. However, you can only
configure one logical link (using one pair of ATM ports) for each ATM cluster-to-cluster trunk
connection.
Guidelines for NNI Trunks via Static Routes:
Ÿ Parallel NNI links may be defined between clusters in separate subnetworks.
Ÿ The maximum number of Static Routes associated to local ATM Cluster Numbers (ACNs) is 50.
Ÿ
Due to the lack of dynamic routing on NNI links, it is recommended that you design networks where
all the clusters are adjacent, as shown in Figure 18 on page 37.
See also “General Guidelines for Configuring Trunks” on page 44 for further information.
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IBM 8285 Nways ATM Workgroup Switch: Installation and User’s Guide