Black Box LR1102A-T1/E1 manual Mutlilink Frame Relay, 27.1Multilink Frame Relay FRF.15 and FRF.16

27

MUTLILINK FRAME RELAY

27.1Multilink Frame Relay FRF.15 and FRF.16

Multilink Frame Relay (MFR) is actually composed of two standards: FRF.15 and FRF.16. The latter is more common and defines UNI/NNI interfaces for implementing MFR. FRF.16 is used for multiplexing dedicated T1s in the local loop and requires compatible equipment at the carrier POP. FRF.15, or DTE-to-DTE MFR is used for multiplexing frame relay T1s between end points without impacting POP equipment. As a result, FRF.15 can be implemented across multiple frame relay carriers to provide additional redundancy. This application discusses considerations for using this standard. All Black Box products support FRF.15 and FRF.16.

27.1.1 Features

„Low cost way of providing added bandwidth to private networks

„Can be done without the knowledge of the Frame Relay provider

„Scalable bandwidth using MFR for customers based on T1 access

„Traffic can be routed or switched using Frame Relay at the end points

A customer desiring to implement DTE-to-DTE MFR can use the architecture illustrated in Figure 1. The normal ordering process can be used to obtain the fame relay T1s. From the perspective of the CPE, the Black Box LR1114As combine those different frame relay PVCs into a consolidated, larger pipe.

FRF.15 uses an aggregated virtual circuit (AVC) for the combined interface. The AVC is composed of constituent virtual circuits (CVC) that represent the frame relay T1s ordered from the carrier(s). In this example, the Black Box LR1114As are configured with DTE LMI; the carrier frame switches are DCE.

Figure 44 MFR Using FRF.15

LR1114A LR1114A

T1	Bundle	DLCI
1	cvc1	101
2	cvc2	102
3	cvc3	103

avc frf15	avc frf15
DLCI 100	DLCI 100
ip addr 11.1.1.1/30	ip addr 11.1.1.2/30

T1	Bundle	DLCI
1	cvc1	101
2	cvc2	102
3	cvc3	103

Frame Relay

Backbone

Frame	Frame
Switch	Switch

In Black Box systems, CVCs are configured using the bundle construct normally used for a non-ethernet interface. After the CVCs are configured, they can be assigned to the AVC. The AVC, frf15 in this case, is assigned a DLCI of 100 on both ends and an IP address in the 11.1.1.0/30 subnet. The AVC names and DLCI numbers can be different on