2-13Configuring a Classical IP ATM Network2.3.5 Operational IssuesCertain hosts in an LIS may not support Classical IP. It is still possible to com-municate with these hosts (and for these hosts to communicate with oneanother) by using static ARP entries. If a host does not support Classical IP, itsIP-to-ATM address mapping should be placed in its ARP server’s cache as astatic entry. This allows other hosts that do support Classical IP to contacttheir ARP server as usual and obtain the correct address mapping. If a hostthat does not support Classical IP wants to initiate connections, the IP-to-ATM address mappings of the destination hosts should be put in its ARPcache, again as static entries. By using static ARP entries in the above fashion,the ability for all hosts to communicate is maintained.There are some restrictions on the number of hosts that can be maintained asstatic ARP entries. They are as follows:• In the default configuration, a host can only have approximately 250virtual connections open simultaneously. This means that an ARPserver can only serve 250 clients, since each client must maintain aconnection with its ARP server. This may be a limitation if the ARPserver is servicing multiple LISs.• On the host, it is possible to increase the number of connectionsallowed by first using cpath (8c) to delete path 0 for the given port,and then using cpath to recreate path 0 for the given port, but usingthe -v option to cpath to specify the number of connections to allowover that path.• Hosts support a maximum of 1,024 connections.
