Network and Management Overview

TFTP

Trivial File Transfer Protocol (TFTP) is used to download networking image code to the Megabit Modem CRA-C from a TFTP server. This allows software upgrades to be performed over the network. The Megabit Modem CRA-C initiates a TFTP download of application code in these situations:

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current application code is not valid; this occurs when the CRC calculated on power-up doesn't match the expected CRC

user sets the value of Image Load Mode to NETWORK, save the configuration to flash, and reboots the Megabit Modem CRA-C

In either case, the Megabit Modem CRA-C performs a BOOTP request first to get the most current network configuration. If the BOOTP fails, the TFTP session is attempted.

TFTP conforms to RFC 1350: The TFTP Protocol (Revision 2)

TFTP uses the connectionless User Datagram Protocol (UDP) for file transfer with minimum overhead.

Encapsulation Protocols

You can select from two packet encapsulation formats for data transported across the ADSL WAN link: Point-to-Point Protocol (PPP) or High-level Data Link Control (HDLC), which is the default. HDLC is the preferred when the system is terminated at each end with PairGain products that have Ethernet ports. PPP is used when interfacing to a WAN port on non-PairGain equipment. In PPP mode, the Megabit Modem CRA-C supports the

Bridge Control Protocol (BCP) RFC 1638 when configured as a bridge

and the Internet Protocol Control Protocol (IPCP) RFC 1332 when configured as a router.

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Megabit Modem CRA-C User Manual