Cisco WS-X6248-RJ-45 - Catalyst 6000 Expansion Module Manual de usuario descargar pdf (Pagina 16)

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Cisco IOS numbers for interfaces start from 1, not 0, for a module; that is, the ﬁrst interface on the line card in slot

2 is 2/1. This is the same port numbering convention that is used with CatOS.

More detailed descriptions of the three primary port types found in Cisco IOS Software are included below.

Routed Interfaces

Cisco IOS Software provides two means for creating Layer 3 interfaces: either at the physical port level (Routed

interfaces, described here) or at the virtual port level (SVIs, described in the following section). With Cisco IOS for

the Cisco Catalyst 6500, each physical port on switch arrives out of the box as a routed interface (just like any Cisco

router).EveryEthernetportonthe switch (whether Fast Ethernet, Gigabit Ethernet, or 10 Gigabit Ethernet) is shown

as interface <interfacetype> <slot/port> and is shutdown by default. This operation differs from CatOS that has all

ports enabled, Layer 2 aware, and in VLAN 1 by default. The routed interface must be conﬁgured on a unique IP

subnet or IPX network. No Layer 2 protocols such as the Spanning Tree Protocol (STP) and DTP are enabled on a

routed interface. CatOS does not support routed interfaces.

For traditional LAN-basedEthernet ports, the routed interface doesnot support subinterface creation for separating

dot1q encapsulations. Similar functionality to IEEE 802.1q subinterfaces is provided with trunk ports, describing in

the following sections.

Layer 2 VLAN

To place several interfaces in the same IP or IPX subnet, the port needs to be converted from a routed interface to a

Layer 2 port so that the portcan be part of the Layer 2 domain orVLAN. The ﬁrst step in this conversion is tocreate

the Layer 2 VLAN entity.

The VLAN ID conﬁguration creates an instance of a Layer 2 broadcast domain or VLAN. The conﬁguration is done

from global conﬁguration mode via a vlan <vlan #> command. VLAN IDs from 1 through 4094 are supported.

VLAN IDs 1002 to 1005 are VTP default VLANs in both CatOS and Cisco IOS and are not user conﬁgurable.

Both the CatOS and Cisco IOS Software support the creation of 4094 Layer 2 VLANs. For a system to be able to

handle 4094 VLAN, a MAC-address reduction feature must be enabled so that the system can allocate a limited

number of system MAC addresses more efﬁciently. The following commands enable this feature.

Routed SVIs

When multiple ports on the same device belong to a single subnet, a VLAN is created to isolate these ports at Layer

2(seeLayer 2 VLAN, above).Generally,these ports need tosendtrafﬁcto other subnets orVLANs.Thisrequirement

is accomplished by creating an SVI to provide the inter-VLAN routing functionality. Just as in the hybrid software

model, SVIs are identiﬁed as interface VLAN 1, interface VLAN 2, etc. These interfaces are associated with Layer 3

CatOS Cisco IOS Software

set vlan 8 IOS#configure terminal

IOS(config)#vlan 8

IOS(config-vlan)#exit

CatOS Cisco IOS Software

set spantree macreduction enable IOS(config)# spanning-tree extend system-id

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Cisco WS-X6248-RJ-45 - Catalyst 6000 Expansion Module Manual de usuario Pagina 16