© Ascend Communications, Inc. All rights reserved. - - - analog versus digital asynchronous vs synchronous BOOTP BOOTP or DHCP relay bridging vs routing circuit-switched services DHCP spoofing Domain Name Service filtering firewalls frame relay IP address format IPX, IP, and Appletalk ISDN service ISDN under the hood packet-switched services RIP SNMP static vs dynamic filtering subnet masks twisted copper pair