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nx.os.and.cisco.nexus.switching.2nd.edition.1587143046

Nexus Switching 2nd Edition

Nexus Switching 2nd Edition

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Eth100/1/46 Up Po100 Po100<br />

Eth100/1/47 Up Po100 Po100<br />

Eth100/1/48 Up Po100 Po100<br />

Logs:<br />

[02/08/2010 18:26:44.953152] Module register received<br />

[02/08/2010 18:26:44.954622] Registration response sent<br />

[02/08/2010 18:26:44.989224] Module Online Sequence<br />

[02/08/2010 18:26:46.868753] Module Online<br />

[02/08/2010 19:15:20.492760] Module disconnected<br />

[02/08/2010 19:15:20.493584] Offlining Module<br />

[02/08/2010 19:15:20.494099] Module Offline Sequence<br />

[02/08/2010 19:15:20.905145] Module Offline<br />

[02/08/2010 19:15:57.354031] Module register received<br />

[02/08/2010 19:15:57.355002] Registration response sent<br />

[02/08/2010 19:15:57.383437] Module Online Sequence<br />

[02/08/2010 19:15:59.212748] Module Online<br />

NX5000#<br />

Layer 2 Forwarding on a Nexus 7000<br />

The Nexus 7000 is an entirely distributed Layer 2 forwarding platform. This means that<br />

every module in the system contains its own forwarding table. When a packet is received on<br />

a port, the ingress module performs both an ingress L2 lookup <strong>and</strong> an initial egress L2<br />

lookup. When the packet arrives at the egress module, a second egress lookup is performed<br />

to ensure that the table has not changed. Each module is also responsible for learning MAC<br />

addresses in the local hardware. MAC addresses learned by an individual module are<br />

flooded acr<strong>os</strong>s the fabric to all other modules in the system, <strong>and</strong> an additional software<br />

process ensures that MAC addresses are properly synchronized acr<strong>os</strong>s the hardware<br />

modules. Aging of MAC addresses is also done locally by each linecard but only for<br />

primary entries (entries learned locally). When a module ages a MAC address, it also<br />

notifies the supervisors so that the address can be removed from the other modules. MAC<br />

address aging is configurable on a per-VLAN basis, with a limit of 14 unique aging values<br />

per system.<br />

To configure the MAC address aging timer, enter the following comm<strong>and</strong>s:<br />

Click here to view code image<br />

N7K-1# config t<br />

N7K-1(config)# mac address-table static 0A11.1111.1111<br />

vlan 10 interface e1/1<br />

N7K-1(config)# exit<br />

To create a static MAC entry, enter the following comm<strong>and</strong>:<br />

Click here to view code image<br />

N7K-1# config t

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