700 Series - Interoperability [Cisco 700 Series ISDN Access Routers]

Document ID: 10248

Questions

Introduction
Are there any interoperability issues between Ascend IP Control Protocol (IPCP) and the Cisco 700 Series Routers?
I am having trouble in the transfer or ftp of large files between a 700 Series Router and a US Robotics (USR) device. Any hints?
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Related Information

Introduction

Refer to Cisco Technical Tips Conventions for more information on document conventions.

Q. Are there any interoperability issues between Ascend IP Control Protocol (IPCP) and the Cisco 700 Series Routers?

A. As far as (IPCP) dynamic IP address assignments go, Cisco IOS®-700 (versions 4.0 and later) does not have any interoperability issues with Ascend. With 4.0(2) and with 4.0(1), you should be able to use DHCP server functionality in conjunction with Port Address Translation (PAT) and dynamic IP address assignment, even with two WAN interfaces simultaneously (such as one to a MAX and one to an AS5200 concurrently). The 4.0(2) version is recommended for this scenario because it contains a new command, which is not in 4.0(1). This command forces the negotiated IP address to the WAN/User profile: set ppp address negotiation local on | off.

Refer to Sample ISDN Configurations for 7XX Products (for this type of usage) for more information.

Q. I am having trouble in the transfer or ftp of large files between a 700 Series Router and a US Robotics (USR) device. Any hints?

A. Extend the PPP integrity time. Some USRs have trouble in the response to echo-requests during the file transfer. The extension of the time can help, but it might not completely resolve the issue.

In accordance to PPP RFC 1331 , an implementation must respond to the link control protocol (LCP) echo-request with LCP echo-reply, but the sending of LCP echo-request is optional. This is directional-independent, which means both sides can send LCP echo-requests. It is only required that the receiving end responds with LCP echo-reply. Most routers use this LCP option to validate the integrity of the link, loopback testing/detection, and so on. However, for client implementations such as Win95, the routers do not perform this. Most routers, such as the Cisco 700, provide a knob to turn this on or off.

If the remote end is either a device of the USR, or it does not support PPP LCP echo-request/reply (most routers do), then you can issue the SEt PPp NEgotiation INtegrity OFf command in order to turn this link integrity check off (on the 7xx). Because this is a system command, use it sparingly (unless a remote device does not support it).