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Community Member

Couples of Questions

Hi!

i have a couples of questions:

Frame-relay

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1)where/when we use like this map in frame-relay:

frame-relay map ip 12.12.34.6 dlci (to remote peer)

frame-relay map ip 12.12.34.5(map to router it self)

Switching

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1)where/when WE USE Like this config.and what it does?

Mls qos

ont f0/0

mpls qos COS 1

2)where/when WE USE Like this config.and what it does?

Remote-span

3)where/when WE USE Like this config.and what it does?

Spaning-tree vlan 10 forward-delay 12

10xs

Ali

NOTE:UR BREIF EXPLANATION ITSVERY MUCH APPRECIATED

3 REPLIES
Community Member

Re: Couples of Questions

Response to Frame Relay question No.1:

You may map an IP address to a specific PVC (DLCI) when dynamic mapping via inverse-arp can't work. Mapping to the router itself is a nonsense.

Remember that by default any frame-relay interface is point-to-multipoint.

Example 1:

There's no LMI therefore there's no automatic DLCI learning. With static mapping is no need of inverse-arp.

interface serial 0

ip address 12.12.34.5 255.255.255.252

encapsulation frame-relay

frame-relay map ip 12.12.34.6 dlci 123

no keepalive

Example 2:

There's no LMI but the DLCI is static declared. The mapping will occur dynamically via inverse-arp if the other end of the PVC will fit in the same subnet.

interface serial 0

ip address 12.12.34.5 255.255.255.252

encapsulation frame-relay

frame-relay interface-dlci 123

no keepalive

Example 3:

There is LMI running and dynamic mapping via inverse-arp.

interface serial 0

ip address 12.12.34.5 255.255.255.252

encapsulation frame-relay

Use the command "show frame-relay map" to observe the PVC mappings. Remember that IP protocol only can be mapped dynamically with inverse-arp.

Re: Couples of Questions

Frame-relay

1. DLCI identifies each link / channel uniquely. If 2 sites A & B are connected by frame-relay, A & B have different DLCI No's.

The command mentioned maps remote peer to a local link identifier. e.g. On rtr A, ip add wud be tht of rtr B, while DLCI is the one configured on link of rtr A.

Switching

2. When ur sniffing a switchport & capturing a output, the concept is known as SPAN. Here, ur source & destination ports shud be on same switch. In RSPAN or Remote-span, sniffing is done across switches i.e. sorce port will be on 1 switch while destination on other.

3. By this command, u can reduce the time taken by a trunkport to transition to forwarding state. By default it is 50 sec. With the command mentioned, it wud take 12 sec for each state i.e. listenign, learning & fwding. So, the port wud transition to fwd state in just 36 sec instead of 50.

Community Member

Re: Couples of Questions

Hello

10xs for ur reply,but i diddn't understand why the router has map to it self to to its ip address too

10xs

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