Ch6 Static Routes Flashcards
Router Learning Methods
- Static
2. Dynamic
Static Route Advantages (3)
- Better security due to routes not being advertised
- Use less bandwidth/cpu than dynamic routing.
- Path of Static route is known; easier to troubleshoot
Static Route Disadvantages (5)
- Initial config and maintenance is time consuming
- Config is prone to errors
- Admin intervention is required to maintain changing route info
- Doesn’t scale well with growing networks
- Complete knowledge of entire network is required for proper use.
Types of Static Routes (4)
- Standard Static Route
- Default Static Route
- Summary Static Route
- Floating Static Route
Standard Static Route
Used when connecting to a specific remote network
Default Static Route (4)
- Route that identifies the gateway IP address to which the router sends all IP packets that it does not have a learned or static route for.
- Matches all packets.
- aka. Quad Zero Route
- Creates Gateway of Last Resort
Summary Static Route
Multiple routes that are summarized into one IP network address.
When can Summary Static Routes be used (2)
- When dest. networks are contiguous and can be summarized into one IP address.
- Multiple static routes all use same exit interface or next-hop IP address
Floating Static Route
- Route used to provide back up routes to a primary static or dynamic route.
- Sets higher Administrative Distance on Floating Static Route than on other routes. When normal route becomes unusable, routing defaults to floating static route.
Configure Static IPv4 Static Route
ip route destination_network_address dest_subnet_mask {exit_interface | next_hop_ip_address}
Next-Hop Static Route (2)
- aka Recursive Route
2. Static Route that uses the next-hop IP address to determine where to send data to reach the destination network.
Directly Connected Static Route (3)
- Used prior to Cisco Express Forwarding (CEF)
- Uses exit interface to determine next hop.
- Route is displayed as directly connected , but still has an AD of 1.
Fully Specified Static Route (2)
- Uses both next-hop IP address and exit interface.
2. Used in older pre-CEF IOSs
Configure Fully Specified Static Route
ip route destination_IP_network_address dest_subnet_mask exit_interface next_hop_IP_address
Methods to Verify Static Route (6)
- ping and traceroute cmds
- show ip route
- show ip route static - displays static routes only
- show ip route connected - shows direct connect routes only.
- show ip route ip_address - shows route table information specific to the ip_address given.
- show running-config | section ip route
Configure Default Static Route
ip route 0.0.0.0 0.0.0.0 {exit_inteface | next_hop_ip}
Configure IPv6 Static Route (2)
- ipv6 unicast-routing //enables ipv6 routing
2. ipv6 route dest_ipv6_address / prefix_length {exit_interface | next_hop_IPv6_address}
Configure IPv6 Default Static Route (2)
- ipv6 unicast-routing // if not already enabled
2. ipv6 route ::/0 {exit_interface | ipv6_next_hop_address}
Classful Addressing
Breakdown of available IP addresses into Classes A through E.
Class A Addresses (3)
- 0.0.0.0 to 127.255.255.255
- Default Subnet: 255.0.0.0
- Large Organizations
Class B Addresses (3)
- 128.0.0.0 to 191.255.255.255
- Default Subnet: 255.255.0.0
- Medium to Large Organizations
Class C Addresses (3)
- 192.0.0.0 to 223.255.255.255
- Default Subnet: 255.255.255.0
- Small to Medium Organizations
Class D Addresses (3)
- 224.0.0.0 to 239.255.255.255
- Default Subnet: non-defined.
- Multicast Addresses
Class E Addresses (3)
- 240.0.0.0 to 255.255.255.255
- Default Subnet: non-defined
- Experimental / Reserved
Private Address Ranges (3)
- ) 10.0.0.0 to 10.255.255.255
- ) 172.16.0.0 to 172.31.255.255
- ) 192.168.0.0 to 192.168.255.255
CIDR (3)
- ) Classless Inter-Domain Routing
- ) Allows creation of subnets not tied to Class License
- ) Allows route summarization / supernetting.
route summarization (2)
- ) aka route aggregation
2. ) multiple static routes are summarized into a single route / ip network address.
supernet (2)
- ) When route summarization mask is a smaller value than the default traditional classful subnet mask.
- ) Supernets are always route summaries but route summaries are not always supernets.
Summarize IPv4 Static Routes (4)
- ) Translate network addresses to binary form.
- ) Count number of far left matching bits; these become the prefix length/subnet mask.
- ) Copy matching bits from all the addresses from step 2 into a new IP network address add 0’s after matching bits.
- ) Make sure to match all matching bits not just 1’s.
Classless Routing Protocols (3)
- ) RIPv2
- ) Open Shortest Path First (OSPF)
- ) Enhanced Interior Gateway Routing Protocol (EIGRP)
Summarizing IPv6 Static Routes (5)
- ) Convert IPv6 addresses to binary. (best to start with the address where a change occurs)
- ) Count far left matching bits; these become prefix length.
- ) Copy matching bits from all addresses from step 2 into a new binary string representing the IPv6 address.
- ) Convert binary into hex (4 bits = 1 hex digit).
- ) Uses same types of static addresses (next-hop, fully, defined, exit interface, etc) as IPv4.
Common Administrative Distances (5)
- ) EIGRP : 90
- ) IGRP: 100
- ) OSPF: 110
- ) IS-IS: 115
- ) RIP: 120
Configure Static Floating Route
ip route dest_ip_address subnet_mask {exit_interface | next_hop_ip} administrative_distance
Methods to Troubleshoot Static Routes (5)
- ) ping or extended ping
- ) traceroute
- ) show ip route
- ) show ip interface brief - displays interfaces with IP addresses and status
- ) show cdp neighbors detail - displays what devices are connected to a specific device using Cisco Discovery Protocol
Extended Ping
- Ping where the destination address is specified as well as the source address for the ping.
- ) Source can be another device in the network not necessarily the router/switch
- ) ping destination_ip_address source_ip_address
Configure Default Static Floating Route
ip route 0.0.0.0 0.0.0.0 {next_hop_ip | exit_interface} Adminstrative_Distance