>From IS-IS Network Design Solutions book:
Multipoint Connections: Frame Relay, ATM, and IS-IS Mesh Solutions IS-IS does not directly support NBMA transport and certainly does make provisions for pointto- multipoint network model. This raises an intriguing question: How do you model nonbroadcast multiaccess (NBMA) networks, such as Frame Relay and ATM? The answer is that you can use a broadcast or point-to-point model. In order to model an NBMA network as a multipoint broadcast LAN, you need full connectivity between all nodes and, therefore, full mesh of permanent virtual circuits between all routers connected to the medium. This is not always possible because most NBMA environments are designed as a hub and spoke architecture, or the NBMA cloud is simply not fully meshed for economic or feasibility reasons. Regards, Antonio Soares, CCIE #18473 (R&S/SP) <mailto:[email protected]> [email protected] <http://www.ccie18473.net> http://www.ccie18473.net From: [email protected] [mailto:[email protected]] On Behalf Of Tyson Scott Sent: quinta-feira, 31 de Março de 2011 18:13 To: 'Vitkovsky, Adam'; [email protected] Subject: Re: [OSL | CCIE_SP] ISIS over NBMA I have never had success running ISIS over hub and spoke. Convert the Hub to a p2p for each spoke and it will work fine. Regards, Tyson Scott - CCIE #13513 R&S, Security, and SP Managing Partner / Sr. Instructor - IPexpert, Inc. Mailto: [email protected] Telephone: +1.810.326.1444, ext. 208 Live Assistance, Please visit: www.ipexpert.com/chat eFax: +1.810.454.0130 IPexpert is a premier provider of Self-Study Workbooks, Video on Demand, Audio Tools, Online Hardware Rental and Classroom Training for the Cisco CCIE (R&S, Voice, Security & Service Provider) certification(s) with training locations throughout the United States, Europe, South Asia and Australia. Be sure to visit our online communities at www.ipexpert.com/communities and our public website at www.ipexpert.com <http://www.ipexpert.com/> From: [email protected] [mailto:[email protected]] On Behalf Of Vitkovsky, Adam Sent: Thursday, March 31, 2011 6:51 AM To: [email protected] Subject: [OSL | CCIE_SP] ISIS over NBMA Hi there, I have hub and spoke topology over main serial interfaces on hub and spokes and ISIS L1 running through Name loopback int-ip R1 1.1.1.1 10.0.0.1 R2 2.2.2.2 10.0.0.2 R3 3.3.3.3 10.0.0.3 R4 4.4.4.4 10.0.0.4 ISIS should behave as on broadcast medium in this setup hub has the highest loopback ip 4.4.4.4 so it became a DIS and is indeed sending the CSNP periodically After initial convergence all the routers have the same topology tables with all the routers loopback IPs Problem is only the hub loopback ip makes it into the routing table on spokes Hub has all 3 spokes loopbacks in its routing table -no issues there and Im able to ping hubs loopback from each spoke -the only thing I could think of was that maybe on broadcast medium isis wont install prefixes from routers with which it doesnt have an adjacency (cause isis forms an adjacency with all the routers on b-cast medium but for nbma its not so only prefixes from hub where installed in RIB) Please let me know your thoughts Thank you very much ---------------- Spoke conf: interface Serial1/0 ip address 10.0.0.1 255.255.255.0 ip router isis 1 encapsulation frame-relay serial restart-delay 0 frame-relay map ip 10.0.0.4 104 frame-relay map clns 104 broadcast no frame-relay inverse-arp ! router isis 1 net 49.0001.0000.0000.0001.00 is-type level-1 log-adjacency-changes all passive-interface Loopback0 ---------------- hub config: interface Serial1/0 ip address 10.0.0.4 255.255.255.0 ip router isis 1 encapsulation frame-relay serial restart-delay 0 frame-relay map clns 403 broadcast frame-relay map clns 402 broadcast frame-relay map clns 401 broadcast frame-relay map ip 10.0.0.3 403 broadcast <-the broadcast keyword doesnt need to be there frame-relay map ip 10.0.0.2 402 broadcast frame-relay map ip 10.0.0.1 401 broadcast no frame-relay inverse-arp ! router isis 1 net 49.0001.0000.0000.0004.00 is-type level-1 log-adjacency-changes all passive-interface Loopback0
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