Flashcards
Frame Relay concepts: PVC, DLCI, LMI and CIR
Flashcards do conjunto (21)
- 1Virtual Circuit (VC)Logical path between DTEs
- 2Permanent Virtual Circuit (PVC)A predefined VC. Analogous to the leased line concept
- 3Switched Virtual Circuit (SVC)A VC that is created and destroyed at will. ISDN, Dial Up
- 4Data Terminal Equipment (DTE)Equipment that connects back to the DCE
Usually the Router configured for Frame Relay - 5Data Communications Equipment (DCE)The Frame Relay switches on the Service Provider network. Connect to the DTE.
- 6Access LinkThe leased line between the DCE and DTE
- 7Committed Information Rate (CIR)A bandwidth amount set by the SP, in which it guarantees to be available for the VC.
- 8Data Link Connection Identifier (DLCI)The frame relay address used in the frame relay headers to ID the VC. These are locally significant.
17 to <1000 - 9Nonbroadcast Multiaccess (NBMA)2 or more device networks but broadcast is not available.
Frame Relay is a NBMA network - 10Local Management Interface (LMI)The protocol used between the DTE and DCE to manage the connection
Defaults to cisco
Other standards are ansi or q933a - 11LMI Message TypesSignaling messages for SVC
PVC Status messages
Keepalives - 12Full MeshAll sites are connected to each other
Mainly a multipoint environment.
Typically 1 subnet - 13Partial MeshOnly part of the network is connected.
Typically a hub and spoke setup
Typically on subnet per VC and use subinterfaces - 14LMI Status Inquiry MessagePerform keep alive on DTE and DCE
Signal whether the PVC is active, inactive, or deleted. - 15PVC Status InactiveThe local DLCI is working properly but there is something wrong with the other end of the PVC
- 16PVC Status ActiveThe Frame Relay network knows about the PVC with the listed DLCI and the PVC is working right now
- 17PVC Status DeletedThe router configuration refers to the DLCI but the LMI is working and lists not information about the DLCI.
The router has the DLCI configured but the FR Switch does not. - 18PVC Status StaticSome DLCI is configured for the PVC but the LMI is down.
Can send frames and hope they can be delivered.
No keepalive is issued on one side of the PVC - 19Discard Eligibility Bit (DE Bit)A bit in a Frame Relay frame's header that indicates the frame was sent in excess of the CIR and can be discarded by the SP if congestion is occurring.
- 20Backward Explicit Congestion Notification (BECN Bit)A bit in a Frame Relay frame's header used to tell the sender to slow down it's transmission rate.
Sent from the receiver back to the sender. - 21Forward Explicit Congestion Notification (FECN Bit)A bit in a Frame Relay frame's header used to tell the receiver to send a frame to the sender, which the service provider will mark with a BECN bit.
Used when traffic is primarily one way like a big download.
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- 2 ICND2 FlashCards sobre Sem título, criado por rekkos em 15-11-2015.
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- rekkos
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