Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Vlan Support for Cisco1721 Modular Router

Hi Team,

This is gurucharan, I would like to know can we configure vlans with cisco 1721 Modular Router? Is it Possible to configure lan environment with the vlans configured in 1721 router without a managed switch?

If it is possible can someone please help me to configure the same.

Thanks with regards,

Gurucharan

Everyone's tags (3)
9 REPLIES

Vlan Support for Cisco1721 Modular Router

Hi Gurucharan,

It is possible to use vlans on the 1721 but you need to have an IOS version other than ip base.

I remember having used IP Plus for this most often.

The router must have sufficient memory and flash to run this image.

http://www.cisco.com/en/US/partner/docs/ios/12_2t/release/notes/122TFEAT.html#wp163875

regards,

Leo

New Member

Vlan Support for Cisco1721 Modular Router

Thanks for your help Leo,

Is it possible to use that vlans without managed switch?

Vlan Support for Cisco1721 Modular Router

Hi Gurucharan,

You can configure vlans in 1721 router that is fine...
But when you need to assign the vlans to end user ports you need a managed switch at least.
In unmanaged switch you can't do any config right? so it is not possible to use vlans in unmanaged switch.

In another way what you can do is, configure vlans in router and then connect your unmanaged switch to the port in the router and then assign particular vlan to that port in router to which you connected your unmanaged switch.

But as long as I know that 1721 have only 1 fastethernet port....


Please rate all the helpfull posts.
Regards,
Naidu.

New Member

Vlan Support for Cisco1721 Modular Router

Hi Naidu,

yes you are right. It has only one eathernet port and 2 wic slots has 5wan ports.

so i want to configure like with one lan network failover for internet. is failover is possible in this?

Regards,

Gurucharan

Vlan Support for Cisco1721 Modular Router

Hi Gurucharan,

so i want to configure like with one lan network failover for internet. is failover is possible in this?
Can you be more detail about it.. Do you need failover between two internet wan links?


Please rate all the helpfull posts.
Regards,
Naidu.

New Member

Vlan Support for Cisco1721 Modular Router

Yes Naidu, want to impliment internet failover with two are more ISP links for internal network.

Vlan Support for Cisco1721 Modular Router

Then the below implementation is what you required.... IP SLA feature.

Hope the below explaination will help you...

R1(config)# ip route 0.0.0.0 0.0.0.0 2.2.2.2

R1(config)# ip route 0.0.0.0 0.0.0.0 3.3.3.3 10

If you notice the Administrative Distance for the secondary route pointing to ISP2 is increased to 10 so that it becomes the backup link.

The above configuration with just two floating static routes partially accomplishes our requirement as it will work only in the scenario where the routers interfaces connected to the WAN link are in up/down or down/down status. But in a lot of situations we see that even though the links remain up but we are not able to reach the gateway, this usually happens when the issue is at the ISP side.

In such scenarios, IP SLAs becomes an engineer's best friend. With around six additional IOS commands we can have a more reliable automatic failover environment.

Using IP SLA the Cisco IOS gets the ability to use Internet Control Message Protocol (ICMP) pings to identify when a WAN link goes down at the remote end and hence allows the initiation of a backup connection from an alternative port. The Reliable Static Routing Backup using Object Tracking feature can ensure reliable backup in the case of several catastrophic events, such as Internet circuit failure or peer device failure.

IP SLA is configured to ping a target, such as a publicly routable IP address or a target inside the corporate network or your next-hop IP on the ISP's router. The pings are routed from the primary interface only. Following a sample configuration of IP SLA to generate icmp ping targeted at the ISP1s next-hop IP.

R1(config)# ip sla 1

R1(config)# icmp-echo 2.2.2.2 source-interface FastEthernet0/0

R1(config)# timeout 1000

R1(config)# threshold 2

R1(config)# frequency 3

R1(config)# ip sla schedule 1 life forever start-time now

The above configuration defines and starts an IP SLA probe.

The ICMP Echo probe sends an ICMP Echo packet to next-hop IP 2.2.2.2 every 3 seconds, as defined by the “frequency” parameter.

Timeout sets the amount of time (in milliseconds) for which the Cisco IOS IP SLAs operation waits for a response from its request packet.

Threshold sets the rising threshold that generates a reaction event and stores history information for the Cisco IOS IP SLAs operation.

After defining the IP SLA operation our next step is to define an object that tracks the SLA probe. This can be accomplished by using the IOS Track Object as shown below:

R1(config)# track 1 ip sla 1 reachability

The above command will track the state of the IP SLA operation. If there are no ping responses from the next-hop IP the track will go down and it will come up when the ip sla operation starts receiving ping response.

To verify the track status use the use the “show track” command as shown below:

R1# show track

Track 1

IP SLA 1 reachability

Reachability is Down

1 change, last change 00:03:19

Latest operation return code: Unknown

The above output shows that the track status is down. Every IP SLAs operation maintains an operation return-code value. This return code is interpreted by the tracking process. The return code may return OK, OverThreshold, and several other return codes.

Different operations may have different return-code values, so only values common to all operation types are used. The below table shows the track states as per the IP SLA return code.

Tracking

Return Code

Track State

Reachability

OK or over threshold

(all other return codes)

Up

Down

The Last step in the IP SLA Reliable Static Route configuration is to add the “track” statement to the default routes pointing to the ISP routers as shown below:

R1(config)# ip route 0.0.0.0 0.0.0.0 2.2.2.2 track 1

R1(config)# ip route 0.0.0.0 0.0.0.0 3.3.3.3 10

The track number keyword and argument combination specifies that the static route will be installed only if the state of the configured track object is up. Hence if the track status is down the secondary route will be used to forward all the traffic.

Please rate the helpfull posts.

Regards,

Naidu.

New Member

Vlan Support for Cisco1721 Modular Router

Thanks Naidu, it will help me to configure my router.

Vlan Support for Cisco1721 Modular Router

Hi Gurucharan,

I am Glad that my efforts helped you.
Please remember to rate all the helpfull posts as it will encourage the others througout this great CSC..


Please rate all the helpfull posts.
Regards,
Naidu.

1421
Views
8
Helpful
9
Replies
CreatePlease login to create content