Topologi
Objective
- Route between VLANs using a 3560 switch with an internal route processor using Cisco Express Forwarding (CEF).
Background
The current network equipment includes a 3560 distribution layer switch and two 2960 access layer switches. The network is segmented into three functional subnets using VLANs for better network management. The VLANs include Finance, Engineering, and a subnet for equipment management, which is the default management VLAN, VLAN 1. After VTP and trunking have been configured for the switches, switched virtual interfaces (SVI) are configured on the distribution layer switch to route between these VLANs, providing full connectivity to the internal network.
Genomförande
Easy! Blir inte så mycket förklaringar här då all konfig är rätt självklar. Först fixar vi upp grundkonfigen:
S1
Switch(config)#hostname S1 S1(config)#line con 0 S1(config-line)#logging sync S1(config-line)#int range fa0/3 - 4 S1(config-if-range)#switchport trunk encaps dot1q S1(config-if-range)#switchport mode trunk S1(config-if-range)#channel-protocol pagp S1(config-if-range)#channel-group 2 mode desirable Creating a port-channel interface Port-channel 2 S1(config-if-range)#int range fa0/1 - 2 S1(config-if-range)#switchport trunk encaps dot1q S1(config-if-range)#switchport mode trunk S1(config-if-range)#channel-protocol pagp S1(config-if-range)#channel-group 1 mode desirable Creating a port-channel interface Port-channel 1 S1(config-if-range)#exit S1(config)#vtp mode server Device mode already VTP SERVER. S1(config)#vtp domain Cisco Changing VTP domain name from NULL to Cisco S1(config)#vlan 100 S1(config-vlan)#name Finance S1(config-vlan)#vlan 200 S1(config-vlan)#name Engineering S1(config-vlan)#exit S1(config)#spanning-tree vlan 1,100,200 root primary S1(config)#
S3
Switch(config)#hostname S3 S3(config)#line con 0 S3(config-line)#logging sync S3(config-line)#int range fa0/1 - 4 S3(config-if-range)#switchport trunk encaps dot1q S3(config-if-range)#switchport mode trunk S3(config-if-range)#int range fa0/1 - 2 S3(config-if-range)#channel-protocol pagp S3(config-if-range)#channel-group 1 mode desirable Creating a port-channel interface Port-channel 1 3(config-if-range)#int range fa0/3 - 4 S3(config-if-range)#channel-protocol pagp S3(config-if-range)#channel-group 2 mode auto Creating a port-channel interface Port-channel 2 S3(config-if-range)#exit S3(config)#vtp domain Cisco Domain name already set to Cisco. S3(config)#vtp mode client Setting device to VTP CLIENT mode.
S2
Switch(config)#hostname S2 S2(config)#int range fa0/1 - 4 S2(config-if-range)#switchport mode trunk S2(config-if-range)#int range fa0/1 - 2 S2(config-if-range)#channel-protocol pagp S2(config-if-range)#channel-group 1 mode auto Creating a port-channel interface Port-channel 1 S2(config-if-range)#int range fa0/3 - 4 S2(config-if-range)#channel-protocol pagp S2(config-if-range)#channel-group 2 mode auto Creating a port-channel interface Port-channel 2 S2(config-if-range)#exit S2(config)#vtp mode client Setting device to VTP CLIENT mode. S2(config)#vtp domain Cisco Domain name already set to Cisco. S2#sh etherchannel summary Flags: D - down P - bundled in port-channel I - stand-alone s - suspended H - Hot-standby (LACP only) R - Layer3 S - Layer2 U - in use f - failed to allocate aggregator M - not in use, minimum links not met u - unsuitable for bundling w - waiting to be aggregated d - default port Number of channel-groups in use: 2 Number of aggregators: 2 Group Port-channel Protocol Ports ------+-------------+-----------+----------------------------------------------- 1 Po1(SU) PAgP Fa0/1(P) Fa0/2(P) 2 Po2(SU) PAgP Fa0/3(P) Fa0/4(P) S3#sh etherchannel summary Flags: D - down P - bundled in port-channel I - stand-alone s - suspended H - Hot-standby (LACP only) R - Layer3 S - Layer2 U - in use f - failed to allocate aggregator M - not in use, minimum links not met u - unsuitable for bundling w - waiting to be aggregated d - default port Number of channel-groups in use: 2 Number of aggregators: 2 Group Port-channel Protocol Ports ------+-------------+-----------+----------------------------------------------- 1 Po1(SU) PAgP Fa0/1(P) Fa0/2(P) 2 Po2(SU) PAgP Fa0/3(P) Fa0/4(P)
Allt ok så långt!
Så då återstår det bara att konfa upp lite L3 SVI’s, vilket är oerhört enkelt egentligen.
S1(config)#interface vlan 1 S1(config-if)#ip add 172.16.1.1 255.255.255.0 S1(config-if)#no shut S1(config-if)#interface vlan 100 S1(config-if)#ip add 172.16.100.1 255.255.255.0 S1(config-if)#no shut S1(config-if)#interface vlan 200 S1(config-if)#ip add 172.16.200.1 255.255.255.0 S1(config-if)#no shut S1(config-if)#exit
Lätt att glömma är att vi även måste aktivera routing-funktionen i switchen!
S1(config)#ip routing
Vi har ju tyvärr ingen host att testa med nu men vi kan åtminstone dra en ping från S3 till något av S1’s vlan.
S3(config)#int vlan 1 S3(config-if)#ip add 172.16.1.3 255.255.255.0 S3(config-if)#no shut S3(config-if)#exit S3(config)#ip default-gateway 172.16.1.1 S3(config)#do ping 172.16.200.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.16.200.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/203/1007 ms
Vackert.
Om vi tar en titt i CEF-table för 172.16.1.3 kan vi se följande:
S1#sh ip cef 172.16.1.3 detail 172.16.1.3/32, epoch 2, flags attached Adj source: IP adj out of Vlan1, addr 172.16.1.3 038C1420 Dependent covered prefix type adjfib cover 172.16.1.0/24 attached to Vlan1
Och switchen har även ett entry i adjacency-table med L2-information för nexthop (S3):
S1#sh adjacency detail Protocol Interface Address IP Vlan1 172.16.1.3(8) 0 packets, 0 bytes epoch 0 sourced in sev-epoch 0 Encap length 14 0014A8899CC00024C33F9EC00800 L2 destination address byte offset 0 L2 destination address byte length 6 Link-type after encap: ip ARP