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Cisco − Configuring Inter−VLAN Routing with Catalyst 3750 Series Switches in a Stacked Configuration
Table of Contents
Configuring Inter−VLAN Routing with Catalyst 3750 Series Switches in a Stacked Configuration.........1
Document ID: 45002................................................................................................................................1
Introduction.....................................................................................................................
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Configuring Inter−VLAN Routing with Catalyst 3750 Series Switches in a Stacked Configuration Document ID: 45002 Introduction Before You Begin Conventions Prerequisites Components Used Background Theory IP Routing on a Stack of 3750s Related Products Configure Network Diagram Practical Tips Configurations Verify Troubleshoot Troubleshooting Procedure Related Information Introduction This document provides a sample configuration for inter
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Components Used The information in this document is based on the software and hardware versions below. • Two Catalyst 3750G−24T switches running 12.1(14)EA1 EMI Software Release stacked together • Catalyst 2950G−48 running 12.1(12c)EA1 EI Software Release • Catalyst 2948G running 6.3(10) Software Release Note: The configuration from the Cisco 7200VXR is not relevant and, therefore, is not shown in this document. The information presented in this document was created from devices in a specific la
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• Generating and distribution of the Distributed Cisco Express Forwarding (dCEF) database to the different stack members • The MAC address of the master is used as source MAC of routed packets • Packets that need process switching are handled by CPU of the master The stack members perform the following tasks: • They act as routing standby switches which can take over when the stack master fails • Programming of the routes in the dCEF database in hardware When the master fails, the stack members
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The above diagram shows a small sample network with the stack of Catalyst 3750s providing inter−VLAN routing between the various segments. The following are the three user defined VLANs: • VLAN 2 − user VLAN • VLAN 3 − server VLAN • VLAN 10 − management VLAN The default gateway configured on each server and host device should be the corresponding VLAN interface IP address on the stack of 3750s. For example, for servers, the default gateway is 10.1.3.1. The Catalyst 2950 is trunked to the top Cat
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• VLAN 1 is not used for management. All ports in Catalyst switches default to VLAN 1, and any devices connected to non−configured ports will be in VLAN 1. This may cause potential issues for the management of switches, as explained above. • A Layer 3 (L3) (routed) port is used to connect to the default gateway port. In this diagram, a Cisco 7200VXR router could be easily replaced by a firewall that connects to the Internet gateway router. A routing protocol is not run between the stack of Catal
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description To 2950 switchport trunk encapsulation dot1q ! !−−− Dot1q trunking (with negotiation) is configured on the L2 switch. !−−− If DTP is not supported on the far switch, issue the !−−− switchport mode trunk command !−−− to force the switch port to trunk mode. !−−− Note: The default trunking mode is dynamic auto. If a trunk link !−−− is established using default trunking mode, it does not appear !−−− in the configuration even though a trunk has been established on !−−− the inter
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interface GigabitEthernet1/0/22 ! interface GigabitEthernet1/0/23 ! interface GigabitEthernet1/0/24 ! interface GigabitEthernet2/0/1 description To 2948G switchport trunk encapsulation dot1q ! !−−− Output suppressed. ! interface GigabitEthernet2/0/23 ! interface GigabitEthernet2/0/24 ! interface Vlan1 no ip address shutdown ! interface Vlan2 description USER_VLAN !−−− This IP address would be the default gateway for users. ip address 10.1.2.1 255.255.255.0 ! interface Vl
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Note: Since the 3750 is configured as a VLAN Trunk Protocol (VTP) server, the VTP configuration is not displayed by the switch. This is standard behavior. The commands below are used on this switch to create a VTP server with the three user−defined VLANs from global configuration mode. C3750G−24T(config)#vtp domain cisco C3750G−24T(config)#vtp mode server C3750G−24T(config)#vlan 2 C3750G−24T(config−vlan)#name USER_VLAN C3750G−24T(config−vlan)#exit C3750G−24T(config)#vlan 3 C3750G−24T(config−vlan
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switchport mode access no ip address spanning−tree portfast ! !−−− Output suppressed. interface GigabitEthernet0/1 switchport trunk encapsulation dot1q no ip address ! interface GigabitEthernet0/2 no ip address ! interface Vlan1 no ip address no ip route−cache shutdown ! interface Vlan10 description MANAGEMENT !−−− IP address used to manage this switch. ip address 10.1.10.2 255.255.255.0 no ip route−cache ! !−−− Default gateway is configured so that the switch is reachable !−−− from oth
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begin ! # ***** NON−DEFAULT CONFIGURATION ***** ! ! #time: Fri Jun 30 1995, 05:04:47 ! #version 6.3(10) ! ! #system web interface version(s) ! #test ! #system set system name Cat2948G ! #frame distribution method set port channel all distribution mac both ! #vtp !−−− VTP domain is configured to be that same as the 3550 (VTP server). set vtp domain cisco !−−− VTP mode is chosen as client for this switch. set vtp mode client ! #ip !−−− The management IP address is configured in VLAN 10. s
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Verify This section provides information you can use to confirm your configuration is working properly. registered customers only Certain show commands are supported by the Output Interpreter Tool ( ) , which allows you to view an analysis of show command output. Catalyst 3750 • show switch − The show switch command tells what the stack consists of and which of stack members is the master. C3750G−24T#show switch Current Switch# Role M
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E1 − OSPF external type 1, E2 − OSPF external type 2, E − EGP i − IS−IS, L1 − IS−IS level−1, L2 − IS−IS level−2, ia − IS−IS inter area * − candidate default, U − per−user static route, o − ODR P − periodic downloaded static route Gateway of last resort is 200.1.1.2 to network 0.0.0.0 200.1.1.0/30 is subnetted, 1 subnets C 200.1.1.0 is directly connected, GigabitEthernet1/0/10 10.0.0.0/24 is subnetted, 3 subnets C 10.1.10.0 is directly connected,
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200.1.1.1 disabled disabled 2−1000 • show trunk Cat2948G> (enable) show trunk * − indicates vtp domain mismatch Port Mode Encapsulation Status Native vlan −−−−−−−− −−−−−−−−−−− −−−−−−−−−−−−− −−−−−−−−−−−− −−−−−−−−−−− 2/49 desirable dot1q trunking 1 Port Vlans allowed on trunk −−−−−−−− −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− 2/49 1−1005 Port Vlans allowed and active in management domain −−−−−−−− −−−
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Updated: Mar 10, 2005 Document ID: 45002 Cisco − Configuring Inter−VLAN Routing with Catalyst 3750 Series Switches in a Stacked Configuration
