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What are the primary uses of static routes?
Providing ease of routing table maintenance in smaller networks that are not expected to grow significantly. Routing to and from stub networks. Using a single default route to represent a path to any network that does not have a more specific match with another route in the routing table. Default routes are used to send traffic to any destination beyond the next upstream router.
What is purpose of a Default Static Route?
Rather than storing all routes to all networks in the routing table, a router can store a single default route to represent any network that is not in the routing table.
What types of static routes were discussed in the chapter?
• Standard static route • Default static route • Summary static route • Floating static route
What is the command to show the ip routes in the running configuration?
show ip route
A default route identifies the ________ IP address to which the router sends all IP packets that it does not have a learned or static route.
gateway
Explain the term route resolvability.
Before any packet is forwarded by a router, the routing table process must determine the exit interface to use to forward the packet.
Describe the importance of a fully specified static route when it comes to point-to-point networks and a multi-access network.
By only designating the Ethernet exit interface in the static route, the router will not have sufficient information to determine which device is the next-hop device.
- Intended for large organizations; includes all addresses from 0.0.0.0 (00000000) to 127.255.255.255 (01111111). The 0.0.0.0 address is reserved for default routing and the 127.0.0.0 address is reserved for loopback testing.
Class A begins with 0
- Intended for medium-to-large organizations; includes all addresses from 128.0.0.0 (10000000) to 191.255.255.255 (10111111).
Class B begins with 10
Recursive lookups should be avoided if possible because?
Recursive lookups consume the routers resources.
What kind of route has both the output interface and the next-hop IP address are specified.
Fully Specified Static Route
A default static route is simply a static route with ___________ as the destination IPv4 address and subnet-mask.
0.0.0.0/0
A directly connected static route is shown in the routing table as "Directly Connected", what will its administrative distance be by default?
1
Class A provides how many networks and hosts?
128 Networks, 16,777,214 Hosts
Class B Provides How many networks and hosts?
16,384 Networks, 65,534 Hosts
Class C Provides How many Networks and hosts?
2,097,152 Networks, 254 Hosts
What is the multicast address of EIGRP?
224.0.0.10
What are the multicast addresses of OSPF?
224.0.0.5 and 224.0.0.6
What is the multicast address of RIP?
224.0.0.9
In a default route, why is the mask a /0?
A /0 mask in this route entry indicates that none of the bits are required to match. The default static route matches all packets for which a more specific match does not exist.
The Gateway of Last Resort is only used when what?
A default route is used when no other routes in the routing table match the destination IP address of the packet.
What is a stub network?
A stub network is a network accessed by a single route, and the router has only one neighbor.
A default static route is also known as what?
Gateway of Last Resort
In the command IP Route where is the administrative distance added? Before or after the exit interface if used?
After the exit interface, which is entered after the IP address of the connecting router used to forward packets to the remote network. AKA Next Hop.
When running the show ip route static command, what special character is displayed next to the "S" code to symbolize that the static route is a default route?
An asterisk "*"
Default static routes are commonly used when connecting what?
An edge router to a service provider network A stub router (a router with only one upstream neighbor router)
What is the command to display the specific route with the address 192.168.2.1?
show ip route 192.168.2.1
- Intended for small-to-medium organizations; includes all addresses from 192.0.0.0 (11000000) to 223.255.255.255 (11011111)
Class C begins with 110
- Multicast addresses are used to identify a group of hosts that are part of a multicast group. This helps reduce the amount of packet processing that is done by hosts, particularly on broadcast media (i.e., Ethernet LANs). Routing protocols, such as RIPv2, EIGRP, and OSPF use designated multicast addresses (RIP = 224.0.0.9, EIGRP = 224.0.0.10, OSPF 224.0.0.5, and 224.0.0.6).
Class D Multicast addresses begin with 1110
These addresses were reserved for experimental and future use.
Class E Reserved IP addresses begin with 1111
What kind of static route is used to connect to a stub network?
Default Static Route
What static route matches all packets?
Default Static Route
What kind of route is a static route that matches all packets?
Default static Route
What older method method on static route configuring was used to prevent recursive lookups?
Directly Connected Static Route
Anytime the network topology changes, how does a static and a dynamic route reconfigure to adjust to the changes.
Dynamic routes change automatically with the use of routing protocols, while static must be manually changed through the network admin.
A static routes that is used to provide a backup path to a primary static or dynamic route, in the event of a link failure is called?
Floating Static Route
What kind of static route is used to create a backup route?
Floating Static Route
The next hop can be identified in what ways?
IP address, exit interface, and both.
What two network protocols support the configuration of static routes?
IPv4 and IPv6
What command must be entered on a router to enable the router to forward IPv6 packets?
IPv6 unicast-routing
What are the disadvantages of static routing compared to dynamic routing?
Initial configuration and maintenance is time-consuming. Configuration is error-prone, especially in large networks. Administrator intervention is required to maintain changing route information. Does not scale well with growing networks; maintenance becomes cumbersome. Requires complete knowledge of the whole network for proper implementation
What is the difference between a directly Connected Static Route and a Next-Hop Static route?
Instead of using the next-hop IP address in the IP ROUTE command it is replaced with the exit interface of the router to the remote network address.
A router can learn about remote networks in what two ways?
Manually and Dynamically
What kind of route can have the administrative distance of 0?
Only a directly connected interface can have an administrative distance of 0.
A next-hop route is specified in the IP route commnad how?
Only the next-hop IP address is added to the IP route command.
A directly connected static route is specified in the IP route command how?
Only the router exit interface is specified.
What two data structures are stored in the data plane in CEF that makes recursive lookups unnecessary and only requires a single routing table lookup?
Routing table and adjacency table. This makes up the Forwarding Information Base.
In order for the Floating Static Route to work properly when the primary route fails, is to do what with the administrative distance?
Set the administrative distance on the Floating Static Route higher than the primary route.
What kind of static route is used to connect to a specific network?
Standard Static Route
What are the advantages of static routing compared to dynamic routing?
Static routes have better security because routes are not advertised over the network. Static routes use less bandwidth than dynamic routing protocols, no CPU cycles are used to calculate and communicate routes. The path of a static route uses to send data is known.
To reduce the number of routing table entries of multiple static routes what type of static route could you implement?
Summary Static Route
What kind of static route is used to summarize routing table entries?
Summary Static Route
What represents the trustworthiness of a route?
The Administrative distance
In the command Ip ROUTE what network address is intermediately followed when configuring a static route?
The Destination network address to be added to the routing table.
When configuring a fully specified static route in IPv6 what must be included from the next hop?
The next hop's link-local address.
A fully specified static route is specified in the IP route command how?
The next-hop IP address and the exit interface are specified.
In the command IP ROUTE 192.168.1.0 the subnet mask following relates to what network?
The remote network to be added to the routing table.
What is the command to display only the static routes in the routing table?
show ip route static
In the command IP ROUTE what is the second IP address relate to?
The second IP address is the IP address of the connecting router to use to forward packets to the remote network. AKA Next Hop
All routes that identify a specific destination with a larger subnet mask take precedence over the default route.
True or False
What is the command and filter to display just the ip route configurations in the running-config?
show running-configuration | section ip route
In a Next-Hop Static Route how many routing table look-ups are required and why when CEF is not being used?
Two routing table look-ups are required. The first time the router looks for a match in the routing table and finds that it has to forward the packets to the next-hop address. The Second time the Router must now determine how to reach next-hp address; therefore, it searches the routing table a second time for a interface that can reach the next-hop address and forwards the packet to that interface.
What is the command to create a default static route to the next hop network with the ip address 192.168.1.0?
ip route 0.0.0.0 0.0.0.0 192.168.1.0
When multiple paths to the destination exist, the router will choose the path with the _________ administrative distance.
lowest
For point-to-point interfaces, you can use static routes that point to the exit interface or to the next-hop address. For multipoint/broadcast interfaces, it is more suitable to use static routes that point to a ___________________.
next-hop address
An IPv4 default static route is commonly referred to as a _______-_______ route.
quad-zero
When the router performs multiple lookups in the routing table before forwarding a packet, it is performing a process known as a ________ __________.
recursive lookup
What are the prerequisites of implementing a Summary Static Route?
• The destination networks are contiguous and can be summarized into a single network address. • The multiple static routes all use the same exit interface or next-hop IP address.
When are default static routes generally used?
• When no other routes in the routing table match the packet destination IP address. (IE a company's edge router that interfaces with the ISP network). • When a router has only one other router to which it is connected. This condition is known as a stub router.
