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Home > Archive > CCNA > March 2002 > Couple Questions~
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| JayDot 2002-03-27, 12:41 pm |
| 1st) Is This Correct
Frame Relay is used on WAN Interfaces to Encapsulate data Cisco(for Cisco EQPT) &
IETF(for Non Cisco EQPT)
2nd) DLCI are used to ID PVC on Frame Relay Interface.... There Can Be many PVC's on interface thus many DLCI on Interface????
Is This Correct...
Say the Wan Interface is T1 which means it has 24DSO Channels are theses the PVC?
3rd) LMI provides INFO about DLCI and PVC
What Kind of INFO does it Provide
Status OF PVC??? WHAT PVC Match up With What DLCI????
and Why are there three values
CISCO,ANSI and Q933a
If anyone could help shed some light on these questions..
Thanx | |
| ROUTERRIP 2002-03-27, 4:40 pm |
| Ok, I'll take a shot at these:
1)That's essentially correct, except I believe you could encapsulate IETF on routers even if there were Cisco brand routers on both ends. IETF is merely encap protocol.
2)Ok, you can have many PVC on a single interface... but only one DLCI which corresponds to that interface. The many other DLCI's correspond to interfaces on other end of PVC. All this within same multipoint mesh or cloud.
Now you could have more than one DLCI on a PHYSICAL interface if your'e using SUBINTERFACES. Logically speaking however, SUBINTERFACES are separate interfaces and thus separate meshes/clouds, etc.
3)LMI is a comm protocol, not really a command. If used within a command, eg. Show LMI status or something like that, I don't think you get much info other than LMI is up or down (meaning router is sending keepalive LMI message to the FR switch). You need a show PVC command to get PVC details.
"What PVC match up with what DLCI?" Might want to rephrase your question so it can be understood. Suffice to say, each PVC will have assigned DLCI on both ends.
Cisco / ANSI /Q933 protocol standards.. eg. Spanish, English, parle vous Francais? | |
| JayDot 2002-03-28, 8:16 am |
| Thanx~
Is this RIGHT??
2 nd)OK There is only ONE DLCI to each interface unless is SUB interface which is logicaly many interfaces but Physicaly one interface.... So can I conclude PVC's are mapped to diffrent DCLI's(interfaces) inside the frame relay encapsulation...
3)LMI is Protocol, used on Frame-relay interfcaes only? What does the Keepalive interval do? I read its default is cisco and autodetected but when would I configure it for ANSI or Q933a .. | |
| ROUTERRIP 2002-03-28, 9:35 am |
| Hey Jay.
2) yes, that basically sounds right. The reason there may be confusion is this: When you are in the router and actually configuring the (multipoint) interface, you are entering all the information (eg. DLCI's) for the OTHER interfaces. In other words, the interfaces that your interface is pointing to. In a multipoint environment this could be several interfaces that your router is pointing to. So when you enter the info, your entering things like, DLCI such and such, IP# such and such, DLCI such and such, IP# such and such, over and over again on YOUR router but these make reference to other router interfaces, not yours.
3) LMI -type Cisco for cisco routers... ANSI and Q933 when working with other router types... or you could configure ANSI /Q933 onto Cisco-to-Cisco.. but why would you.
Autodetect is for DLCI mapping, not LMI type (I believe). |
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