| 1 | At a minimum, each entry of the routing table must include a destination address and the address of a next-hop router or an indication that the destination address is directly connected. |
| 2 | Variably subnetted means that the router knows of more than one subnet mask for subnets of the same major IP address. |
| 3 | Discontiguous subnets are two or more subnets of a major IP network address that are separated by a different major IP address. |
| 4 | show ip route is used to examine the routing table of a Cisco router. |
| 5 | The command show ipv6 route displays the IPv6 route table. Prefixes, prefix lengths, and the next-hop address or outgoing interface are displayed, as are the administrative distance and route metric. |
| 6 | The first bracketed number is the administrative distance of the routing protocol by which the route was learned. The second number is the metric of the route. |
| 7 | When a static route is configured to reference an exit interface instead of a next-hop address, the destination address will be entered into the routing table as directly connected. |
| 8 | A summary route is a single route entry that points to multiple subnets or major IP addresses. In the context of static routes, summary routes can reduce the number of static routes that must be configured. |
| 9 | An administrative distance is a rating of preference for a routing protocol or a static route. Every routing protocol and every static route has an administrative distance associated with it. When a router learns of a destination via more than one routing protocol or static route, it will use the route with the lowest administrative distance. |
| 10 | A floating static route is an alternative route to a destination. The administrative distance is set high enough that the floating static route is used only if a more-preferred route becomes unavailable. |
| 11 | Equal-cost load sharing distributes traffic equally among multiple paths with equal metrics. Unequal-cost load sharing distributes packets among multiple paths with different metrics. The traffic will be distributed inversely proportional to the cost of the routes. |
| 12 | If an inbound interface is configured for CEF, the packet will be switched with CEF, and CEF load balancing rules will apply: per destination or per packet for IPv4, depending upon the configuration, and per destination for IPv6. If CEF is not configured on the inbound interface, the outbound interface determines the switching mode, and thus the method of load sharing. If an outbound interface is fast switched, per destination load sharing is performed. If an interface is process switched, per packet load sharing is performed. |
| 13 | A recursive routing table lookup occurs when a router cannot acquire all the information it needs to forward a packet with a single routing table lookup. For example, the router may perform one lookup to find the route to a destination and then perform another lookup to find a route to the next-hop router of the first route. |
