Chapter 6 intervlanrouting
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This document discusses inter-VLAN routing and configuring a router to route between VLANs. It describes using router subinterfaces to allow a single physical router interface to route traffic for multiple VLANs by assigning each subinterface its own IP address and VLAN encapsulation. The document also briefly mentions using a multilayer switch for inter-VLAN routing and revising VLAN and trunk configuration as prerequisites.
Chapter 6 intervlanrouting
- 1. Inter-VLAN routing CCNA Exploration Semester 3 Chapter 6 30 Sep 2012 S Ward Abingdon and Witney College 1
- 2. Topics Routing network traffic between VLANs Configuring a router for routing between VLANs Troubleshoot inter-VLAN connectivity issues 2 30 Sep 2012 S Ward Abingdon and Witney College
- 3. Semester 3 LAN Design Basic Switch Wireless Concepts VLANs STP VTP Inter-VLAN routing 3 30 Sep 2012 S Ward Abingdon and Witney College
- 4. Inter VLAN routing Switch keeps VLANs separate. Router can route between VLANs (subnets). 4 30 Sep 2012 S Ward Abingdon and Witney College
- 5. Traditional inter-VLAN routing The router has one physical port for each VLAN. Each port has an IP address on its own VLAN. Routing is the same as routing between any subnets. 5 30 Sep 2012 S Ward Abingdon and Witney College
- 6. Traditional inter-VLAN routing Router looks up Router sends out 192.168.2.0 network to packet through F0/1 – port F0/1 F0/2 switchport Send requestto ARP packet to F0/0 MAC address find of router Switchport F0/2 is of default gateway on VLAN30 and forwards to PC3. PC1 has a packet for 192.168.2.19 – different subnet 6 30 Sep 2012 S Ward Abingdon and Witney College
- 7. Traditional inter-VLAN routing Trunks between switches. No trunk to router. No tags on frames to router. 7 30 Sep 2012 S Ward Abingdon and Witney College
- 8. Trunk to the router You soon run out of router ports. What about making a trunk link to the router? A trunk link can be used with several VLANs on the same physical port. But each VLAN needs a different IP address. So use subinterfaces, each with its own IP address. 8 30 Sep 2012 S Ward Abingdon and Witney College
- 9. Router on a stick R1 F0/0 has subinterfaces, one for each VLAN. Each has its own IP address. VLAN tags on trunk. 9 30 Sep 2012 S Ward Abingdon and Witney College
- 10. Availability of trunking Not all routers allow subinterfaces for VLAN trunking on Ethernet ports. It depends on the IOS feature set. Some of ours do, others do not. 10 30 Sep 2012 S Ward Abingdon and Witney College
- 11. Subinterfaces Subinterfaces take the interface name followed by a dot and a number. It is normal to use the VLAN number. If this ties in with the IP address, even better. E.g. interface f0/0.10 The subinterfaces each have an IP address. The physical interface has no IP address The physical interfaces needs no shutdown 11 30 Sep 2012 S Ward Abingdon and Witney College
- 12. Configuring subinterfaces R1(config)#interface f0/0.10 R1(config-subif)#encapsulation dot1q 10 R1(config-subif)#ip address 172.17.10.1 255.255.255.0 (add any other subinterfaces) R1(config-subif)#interface f0/0 R1(config-if)#no shutdown 12 30 Sep 2012 S Ward Abingdon and Witney College
- 13. Routing table Subinterfaces are shown 172.17.0.0/24 is subnetted, 2 subnets C 172.17.10.0 is directly connected, FastEthernet0/0.10 C 172.17.30.0 is directly connected, FastEthernet0/0.30 13 30 Sep 2012 S Ward Abingdon and Witney College
- 14. Subinterface considerations Routers have a limited number of interfaces, so subinterfaces help where there are many VLANs. Subinterfaces share the bandwidth on a physical interface so can cause bottlenecks. Cheaper to use subinterfaces. Simpler physical layout but more complex configuration with subinterfaces. 14 30 Sep 2012 S Ward Abingdon and Witney College
- 15. Multilayer switch A multilayer switch can route between VLANs. But that’s CCNP. 15 30 Sep 2012 S Ward Abingdon and Witney College
- 16. Revision There is some revision of setting up VLANs and VLAN trunking. Much of the router material is revision because semester 3 can be taken before or alongside semester 2. 16 30 Sep 2012 S Ward Abingdon and Witney College
- 17. Troubleshooting Check physical connections Check switchport VLAN assigment Check trunking on switches Check IP addressing and subnetting scheme in relation to VLANs Check router subinterface configuration 17 30 Sep 2012 S Ward Abingdon and Witney College
- 18. The End 30 Sep 2012 S Ward Abingdon and Witney College 18