Chapter 12

p. 169, l.3

Broadcasting and multicasting can apply to protocols other than UDP (though not to TCP). Examples are OSPF (multicast); ICMP (broadcast for router discovery) and IGMP (p. 179).

pp. 171-2

The ``net-directed'' and ``all-subnets-directed'' broadcast are essentially obsolete since CIDR (p. 140).

p. 176

One could ask what the rôle of 224.0.0.1 is -- surely it duplicates the ``limited broadcast'' address 255.255.255.255? In theory that is true, but in practice 224.0.0.1 means, not Stevens' ``all systems on this subnet'', but rather ``all multicast-capable systems on this subnet''. Many systems, e.g. printers, are sold without multicasting, since there is no need for it, and, as we have seen, it complicates the Ethernet interface, device driver, and the IP layer.