Routed port on Layer 3 switch ?? please help

Answered Question
Mar 2nd, 2010
User Badges:

Hello everyone


I am confuse about the routed port on layer 3 switch , Can someone please help me out why we have to configure routed port on the layer 3 switch .

As we all know that layer 3 switch can do VLAN routing then we need to configure routed port on the layer 3 switch and connect router on that port

what is purpose of confgureing routed port , I am totally confuse about the concept of routed port


please help me out


Thanks

Correct Answer by Ganesh Hariharan about 7 years 4 months ago


Hello everyone


I am confuse about the routed port on layer 3 switch , Can someone please help me out why we have to configure routed port on the layer 3 switch .

As we all know that layer 3 switch can do VLAN routing then we need to configure routed port on the layer 3 switch and connect router on that port

what is purpose of confgureing routed port , I am totally confuse about the concept of routed port


please help me out


Thanks


Hi,


Routed port by defination is a physical port that acts like a port on a router. A routed port is not associated with a particular VLAN, and it behaves like a regular router interface. You can configure a routed port with a Layer 3 routing protocol.A routed port is useful if you want to IP terminate something on the


switch and not get the traffic on that port mixed in with other L2 traffic.


Hope to Help !!


Remember to rate the helpful post


Ganesh.H

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (1 ratings)
Loading.
Aaron D Tue, 03/02/2010 - 07:46
User Badges:

routed port is for Layer 3 (like a WAN link on a switch) and is configured with the no switchport command. switchport tu

rns the port into layer 2 for trunking or VLAN assignment. Routed ports are used commonly for Layer 3

core's where all links are Layer 3 since its failover mechanism

s are faster and more effective than Layer 2.

timtech2631 Tue, 03/02/2010 - 08:33
User Badges:

Thanks


so it means that the routed port can only use for the WAN link let say I have frame relay configure for the client on my router with different ip address so I want to allow my client ip network to be routed inside my network so i have achive this by doing routed port correct me


Thanks

Jon Marshall Tue, 03/02/2010 - 08:37
User Badges:
  • Super Blue, 32500 points or more
  • Hall of Fame,

    Founding Member

  • Cisco Designated VIP,

    2017 LAN, WAN

timtech2631 wrote:


Thanks


so it means that the routed port can only use for the WAN link let say I have frame relay configure for the client on my router with different ip address so I want to allow my client ip network to be routed inside my network so i have achive this by doing routed port correct me


Thanks


A routed port is just a L3 port. It does not have to be WAN it can be within your LAN ie. you want to connect your L3 switch to a router that then sends traffic somwhere else. You can connect the L3 switch to the router using a routed port on the L3 switch.


As for frame-relay, actually on switches you generally wouldn't be able to terminate a frame-relay connection. L3 routed ports on L3 switches are for ethernet.


Jon

Jon Marshall Tue, 03/02/2010 - 07:49
User Badges:
  • Super Blue, 32500 points or more
  • Hall of Fame,

    Founding Member

  • Cisco Designated VIP,

    2017 LAN, WAN

timtech2631 wrote:


Hello everyone


I am confuse about the routed port on layer 3 switch , Can someone please help me out why we have to configure routed port on the layer 3 switch .

As we all know that layer 3 switch can do VLAN routing then we need to configure routed port on the layer 3 switch and connect router on that port

what is purpose of confgureing routed port , I am totally confuse about the concept of routed port


please help me out


Thanks


Routed ports works at L3 and not L2. So there is no STP (Spanning-tree) running on the port if you configure it as a routed port. Generally speaking routed ports are good when you are using a L3  point to point link between your L3 switch and another L3 switch or router.


Jon

Giuseppe Larosa Tue, 03/02/2010 - 07:50
User Badges:
  • Super Silver, 17500 points or more
  • Hall of Fame,

    Founding Member

Hello Tim,

the option of using a routed port can be helpful in some scenarios where you want to be sure that if that port goes down the L3 interface goes down too.


When we use L2 Vlans and their L3 associated objects SVI interfaces there is a mechanism called autostate:

the SVI is considered up/up if at least one L2 port is operational and in STP forwarding state.


So using an SVI can lead to an undesired behavior in some cases because also L2 trunks count for that check and it is enough to have the vlan permitted and in STP forwarding state to have the SVI up/up.


Another benefit of using routed ports is that on them STP is not running and so routing  convergence depends only from routing protocol capabilities and no STP is involved


Hope to help

Giuseppe

Correct Answer
Ganesh Hariharan Tue, 03/02/2010 - 08:34
User Badges:
  • Purple, 4500 points or more
  • Community Spotlight Award,

    Member's Choice, February 2016


Hello everyone


I am confuse about the routed port on layer 3 switch , Can someone please help me out why we have to configure routed port on the layer 3 switch .

As we all know that layer 3 switch can do VLAN routing then we need to configure routed port on the layer 3 switch and connect router on that port

what is purpose of confgureing routed port , I am totally confuse about the concept of routed port


please help me out


Thanks


Hi,


Routed port by defination is a physical port that acts like a port on a router. A routed port is not associated with a particular VLAN, and it behaves like a regular router interface. You can configure a routed port with a Layer 3 routing protocol.A routed port is useful if you want to IP terminate something on the


switch and not get the traffic on that port mixed in with other L2 traffic.


Hope to Help !!


Remember to rate the helpful post


Ganesh.H

Actions

This Discussion