itself because that other router has a better route to the subnet to which the host sent a
packet. The redirect also implies that the router sending the redirect, the host sending the
original packet, and the better router all have interfaces attached to this same subnet.
type of ICMP messages is it receiving?
with UDP as the transport layer protocol, with TTL values beginning at 1 and then
incrementing by 1 in successive messages. The result is that intervening routers will find
that the TTL is exceeded and will send ICMP "TTL exceeded" messages back to the
originator of the packet, which is the router where the trace command is being executed.
The source addresses of the "TTL exceeded" packets identify each router. By sending
other packets with TTL=2, then 3, and so on, eventually the packet is received by the host.
The host returns a "port unreachable" ICMP message, which lets the trace command
know that the endpoint host has been reached.
Layer 3 equivalent when comparing TCP/IP to the OSI protocols?
to be part of TCP/IP's protocols equivalent to OSI Layer 3. ICMP is also considered a
Layer 3 protocol because it is used for control and management of IP. However, an IP
header precedes an ICMP header, so it is common to treat ICMP as another Layer 4
protocol, like TCP and UDP. ICMP does not provide services to a higher layer, so it is
really an adjunct part of Layer 3.
message is not implied by the "U".
elements of each entry.
address, the MAC address, and the interface from which the information was learned. The
encapsulation type is also in the table entry.
many hosts are allowed for 255.255.255.252?
links need only two IP addresses.