A couple of thoughts. First, can I presume from your statement below that you are able to initiate a call from the Cisco router to the IBM 2210 (even if it is not multilink). According to IBM's web site, the 2210 does support PPP multilink. Nevertheless, like Animal Farm's pigs, some support for multilink may be more equal than others. I note on IBM's web page that there is not an explicit support for the RFCs that cover PPP (unlike Cisco's support). This may indicate compatability problems. http://www.networking.ibm.com/220/220over.html#s20 I think you have hit upon a key ingredient for interoperability, namely the negotiated maximum received reconstructed unit (MRRU). To quote from RFC 1990, here is paragraph 5.1.1 (excerpt): The Max-Receive-Reconstructed unit field is two octets, and specifies the maximum number of octets in the Information fields of reassembled packets. A system MUST be able to receive the full 1500 octet Information field of any reassembled PPP packet although it MAY attempt to negotiate a smaller, or larger value. The number 1500 here comes from the specification for the MRU LCP option in PPP; if this requirement is changed in a future version of RFC1661 the same rules will apply here. I think one key to minimizing the headache here will be to go to that MRRU which both hosts must be able to support. If you leave most of your interfaces at their default, a 1500 MRRU should be attainable. While looking to see what configurations commands might affect the MRRU, I noticed that it *appears* the 2210 does not have explicit support for PPP multilink, nor does it *appear* to have an LCP option to negotiate it. I hope I read the IBM configuration guide incorrectly. See chapter 28 (watch wrap): http://publib.boulder.ibm.com/cgi- bin/bookmgr/BOOKS/E2FB5004/CCONTENTS Additionally, this passage from IBM's marketing brochure did not inspire confidence that standards based (RFC 1990) multilink was used in the 2210: http://www.networking.ibm.com/220/220over.html Specifically, "Hardware and software for dependable routing solutions When equipped with one of the many available ISDN adapters, the 2210 Nways Multiprotocol Router and Nways MRS are dependable ISDN solutions. The Quad BRI adapter offers increased bandwidth and provides backup capability without requiring more expensive Primary Rate ISDN (PRI) service. With the Point-to-Point Protocol multilink tool�supplied with the 2210�bandwidth can be increased dynamically by grouping the B-channels. And for even greater bandwidth administration, rely on IBM's award-winning Bandwidth Reservation System (BRS) to manage traffic priority over Frame Relay, PPP and dial connections. I have never heard of multilink referred to as a "tool". HTH, Paul Werner > Subject: Multilink PPP with ISDN between Cisco 2504 and IBM 2210 [Virus > checked] > > Hello all, > > we must install Cisco Router in our IBM environment :)) . We solved a = > lot > of problems but we have one unsolved problem: > > The Cisco router must dialed-in to the IBM router with both ISDN B > channels. The connection comes not up with the feature multilink. We te= > sted > a lot of possibilties: > > - - dial-in Cisco <-> Cisco with and without Multilink is o.k. > - - dial-in IBM <-> IBM with and without Multilink is o.k. > - - dial-in Cisco <-> IBM without Multilink (one ISDN B channel) is also > = > o.k. > > Only the multilink solution between Cisco an IBM doesn=B4t work. > > Have any of you an idea ?? > We think that we have a problem with the LCP layer. For instance how ca= > n I > set the MRRU ? > > Software: c2500-is-l_120-8.bin and eptf09i.e11 > > See the files (configuration of the Cisco router and a debug of the IBM= > ), > please. > > (See attached file: Multilink.log)(See attached file: cisco2504.log) > > Thank=B4s a lot. ________________________________________________ Get your own "800" number Voicemail, fax, email, and a lot more http://www.ureach.com/reg/tag _________________________________ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
