intervlan routing design and implementation. what routers do intelligent, dynamic routing protocols...
TRANSCRIPT
![Page 1: InterVLAN Routing Design and Implementation. What Routers Do Intelligent, dynamic routing protocols for packet transport Packet filtering capabilities](https://reader035.vdocuments.us/reader035/viewer/2022072011/56649e115503460f94afcff7/html5/thumbnails/1.jpg)
InterVLAN Routing
Design and Implementation
![Page 2: InterVLAN Routing Design and Implementation. What Routers Do Intelligent, dynamic routing protocols for packet transport Packet filtering capabilities](https://reader035.vdocuments.us/reader035/viewer/2022072011/56649e115503460f94afcff7/html5/thumbnails/2.jpg)
What Routers Do
• Intelligent, dynamic routing protocols for packet transport
• Packet filtering capabilities
• Connectivity enhancements – DHCP, NAT, QoS, policy-based routing
• Connectivity between LAN and WAN
![Page 3: InterVLAN Routing Design and Implementation. What Routers Do Intelligent, dynamic routing protocols for packet transport Packet filtering capabilities](https://reader035.vdocuments.us/reader035/viewer/2022072011/56649e115503460f94afcff7/html5/thumbnails/3.jpg)
Routing Issues
• Isolated broadcast domains– Linked by routers (Layer 3)
• Sending nonlocal packets – Routing protocols, gateway of last resort,
default routes
• Supporting multiple VLAN packets across VLAN boundaries– ISL solves problem
![Page 4: InterVLAN Routing Design and Implementation. What Routers Do Intelligent, dynamic routing protocols for packet transport Packet filtering capabilities](https://reader035.vdocuments.us/reader035/viewer/2022072011/56649e115503460f94afcff7/html5/thumbnails/4.jpg)
ISL
• Supported over Fast Ethernet links– Single ISL link (trunk) can carry traffic from
multiple VLANs• Packets encapsulated with ISL VLAN header
appropriate to destination and routes to appropriate interface
![Page 5: InterVLAN Routing Design and Implementation. What Routers Do Intelligent, dynamic routing protocols for packet transport Packet filtering capabilities](https://reader035.vdocuments.us/reader035/viewer/2022072011/56649e115503460f94afcff7/html5/thumbnails/5.jpg)
Routing in a Switched Network
• interVLAN routing– Add a route processor in switched network to provide layer 3 routing
• Every packet goes through the router
• Layer 3 switching (RSM- route switch module)– Router running IOS software plugs into switch backplane
• Appears as module with single 800 Mb half duplex trunk port and one MAC address
• Multilayer switching (MLS)– Router sees only first packet; sets up switching paths to bypass the
router
• Cisco Express Forwarding (CEF)– Distributed switching mechanism
![Page 6: InterVLAN Routing Design and Implementation. What Routers Do Intelligent, dynamic routing protocols for packet transport Packet filtering capabilities](https://reader035.vdocuments.us/reader035/viewer/2022072011/56649e115503460f94afcff7/html5/thumbnails/6.jpg)
RSM Details
• Provides multilayer switching and inter-VLAN routing between switched VLANs– Can be installed in slots 2 through 12– Maximum number of modules is 7 for Cat 5500– RSM is mapped through VLAN 0 and VLAN 1
• VLAN 0 to channel 0; VLAN 1 to channel 1• VLAN 0 assigned ROM MAC address• VLAN 1 assigned base MAC address from 512
available MAC addresses
![Page 7: InterVLAN Routing Design and Implementation. What Routers Do Intelligent, dynamic routing protocols for packet transport Packet filtering capabilities](https://reader035.vdocuments.us/reader035/viewer/2022072011/56649e115503460f94afcff7/html5/thumbnails/7.jpg)
Routing with Multiple Physical Links
• Use one link for each VLAN on switch to connected router– Each packet travels across a link reserved for VLAN
traffic• Useful when switches and router are already available and can be
quickly connected• Not a good idea to use when network grows
• Trunk links– Use only one link to router – router on a stick or one-
armed router• Integrated Router
– Route processor is inside the switch for tighter integration of layer 2 and layer 3 components
![Page 8: InterVLAN Routing Design and Implementation. What Routers Do Intelligent, dynamic routing protocols for packet transport Packet filtering capabilities](https://reader035.vdocuments.us/reader035/viewer/2022072011/56649e115503460f94afcff7/html5/thumbnails/8.jpg)
Routing Over Trunk Lines
• 802.1q and ISL trunks– Use Fast Ethernet or Gigabit Ethernet– Each frame identified with VLAN number
• Frame encapsulated as it leaves switch
– Offer scalability because single link can transport many VLANs
– Requires link bandwidth overhead• 30-byte header (ISL) or 4-byte header (802.1q)
![Page 9: InterVLAN Routing Design and Implementation. What Routers Do Intelligent, dynamic routing protocols for packet transport Packet filtering capabilities](https://reader035.vdocuments.us/reader035/viewer/2022072011/56649e115503460f94afcff7/html5/thumbnails/9.jpg)
Routing with an Integrated Router
• Route Switch Module (RSM)– Runs Cisco ISO software – Interfaces to switch through backplane – channel 0 and
channel 1• Route processor is module with route switch in the module-
type field– Use show module command– Use session to telnet from switch to router
• Multilayer Switch Feature Card (MSFC)– Shortcuts switch layer 3 and higher protocols – to be
covered in detail later
![Page 10: InterVLAN Routing Design and Implementation. What Routers Do Intelligent, dynamic routing protocols for packet transport Packet filtering capabilities](https://reader035.vdocuments.us/reader035/viewer/2022072011/56649e115503460f94afcff7/html5/thumbnails/10.jpg)
VLAN Connectivity and Trunk lines
• (config)# int 2/3.1
• (config-if)#encap isl vlan2
• Ip address n.n.n.n s.s.s.s– Each subinterface is assigned to specific VLAN– VLAN numbers should match on both router
and switch ends
![Page 11: InterVLAN Routing Design and Implementation. What Routers Do Intelligent, dynamic routing protocols for packet transport Packet filtering capabilities](https://reader035.vdocuments.us/reader035/viewer/2022072011/56649e115503460f94afcff7/html5/thumbnails/11.jpg)
Routing Processes
• Route processor keeps local table of known routes, metrics, interfaces, and neighboring routers– Uses dynamic routing protocols and static routes
– (config)# ip routing
– (config)# router rip
– (config-router)# network n.n.n.n
• Switch (enable) set ip route default gateway