10-29-2009 10:18 AM - edited 03-06-2019 08:22 AM
I have a question about routing an access layer switch rather than trunking. Like the old WAN config, I setup a stub network between routers. This is the same for switches? So, in my configuration, I would need a stub network between the access layer switch and the distribution layer switch.
Example: The access layer switch network is 192.168.15.0/24 config on ports would be:
Access switch:
interface TenGigabitEthernet1/0/1
no switchport
ip address 192.168.60.74 255.255.255.252
Distribution switch:
interface TenGigabitEthernet1/1/8
no switchport
ip address 192.168.60.73 255.255.255.252
No better way to do it? And say I want redundant links, I use another stub network on different ports?
BTY: This works in test. Making sure I'm not missing something here.
Thanks!
10-29-2009 10:33 AM
Hello Alan,
if you have a routed access layer you will have L3 (up)links as the one that you have described in your post.
The alternate way to do this is to use SVIs that would allow you to use multiple L2 links, either bundled or not
vlan 333
name bbone vlan
int vlan 333
ip address 192.168.60.74 255.255.255.252
no shut
int te1/0/1
switchport
switchport mode access
switchport access vlan 333
channel-group 2 mode active
int te1/0/2
switchport
switchport mode access
switchport access vlan 333
channel-group 2 mode active
this would allow you to have a L3 link running over a bundle of 2 TenGiga
be aware that L3 links allow you to have multiple parallel links so you can go on with routed ports but you can deploy multiple links in parallel
Hope to help
Giuseppe
10-29-2009 10:50 AM
I dont like the idea of access vlan on port channel.
You should give an ip address to your port channel interface and bundle your links.
You can assign a port channel interface to a vlan, but dont do it on the interface itself as in this example.
11-02-2009 01:06 PM
Thanks, this makes sense.
I can do port-channel on the access layer switch. Howver, the uplinks go to 2 separate distribution layer switches where I could not port-channel ports on separate switches.
Unless I have VSS on the distribution layer switches, correct?
10-29-2009 04:16 PM
Thanks for the information!
One other scenario I'm facing is that I will be routing between 2 redundant 6500 core switches to a production network with another 2 6500 core switches.
The new production core switches have VSS and I can configure a port channel across switches.
My existing core switches are not VSS capable yet. I assume port channeling with 2 separate core switches is not possible.
Thanks again!
10-29-2009 05:24 PM
Hi Alan,
could you provide more details about the C6500 routing?
If you have a fullmesh, ospf is fine.
If you have a ring topologie and don't like dynamic routing but SPT, just use VRRP or HSRP.
regards
Thilo
10-29-2009 11:03 AM
Hi Alan,
if you want to implement a L3-access design, there are some recommendations:
- implement OSPF or EIGRP
- use stub areas
- implement summarization
- implement equal cost routing for your uplinks
- tune routing-protocol timers to achive very fast convergence
Here's a link to the Solution Reference Network Design - very comprehensive material:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Campus/routed-ex.html
HTH
Rolf
10-29-2009 05:10 PM
Hi Alan,
here an other solution to address your "routing an access layer switch" problem.
At the access layer switch create a vlan, a svi with ip address and two native ethernet uplinks based on FlexLink. With FlexLink, only one link is active, one is in standby, SPT is disabled on both interfaces.
al-switch:
vlan 10
name access-vlan
interface vlan 10
ip address x.x.x.x y.y.y.y
interface g1/0/1
switchport mode access
switchport nonegotiate
switchport access vlan 10
switchport backup interface g1/0/2
interface g1/0/2
switchport mode access
switchport nonegotiate
switchport access vlan 10
FlexLinks are possible at C2960 and higher.
And here the aggregation switch/switches config:
ag-switch/switches:
vlan 10
name access-vlan
interface vlan 10
ip address x.x.x.x y.y.y.y
interface g1/0/1
switchport mode access
switchport nonegotiate
switchport access vlan 10
( inter g1/0/2
switchport mode access
switchport nonegotiate
switchport access vlan 10 )
regards
Thilo
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