ICND1 | Interconnecting Cisco Networking Devices 1

For a trunk link to be established, both ends of the trunk link must be configured to use the same native VLAN. Cisco Discovery Protocol (CDP) will present a native VLAN mismatch error message if the native VLANs do not match. To display the status of the trunk and the native VLAN used on that trunk link, and to verify trunk establishment, you can use the show interface trunk command in privileged EXEC mode.

Cisco Discovery Protocol (CDP) exchanges hardware and software device information with its directly connected CDP neighbors. Although this is a useful troubleshooting tool, it would not prevent hosts from communicating with each other. Dynamic Trunking Protocol (DTP) is a Cisco proprietary protocol used to manage automatic trunk negotiation. Disabling DTP would create further issues, as the trunk link would be disabled. Disabling RSTP would not prevent hosts from communicating with each other unless there was a loop involved.
For a trunk link to be established, both ends of the trunk link must be configured to use the same native VLAN. Cisco Discovery Protocol (CDP) will present a native VLAN mismatch error message if the native VLANs do not match. To display the status of the trunk and the native VLAN used on that trunk link, and to verify trunk establishment, you can use the show interface trunk command in privileged EXEC mode.

Cisco Discovery Protocol (CDP) exchanges hardware and software device information with its directly connected CDP neighbors. Although this is a useful troubleshooting tool, it would not prevent hosts from communicating with each other. Dynamic Trunking Protocol (DTP) is a Cisco proprietary protocol used to manage automatic trunk negotiation. Disabling DTP would create further issues, as the trunk link would be disabled. Disabling RSTP would not prevent hosts from communicating with each other unless there was a loop involved.
For a trunk link to be established, both ends of the trunk link must be configured to use the same native VLAN. Cisco Discovery Protocol (CDP) will present a native VLAN mismatch error message if the native VLANs do not match. To display the status of the trunk and the native VLAN used on that trunk link, and to verify trunk establishment, you can use the show interface trunk command in privileged EXEC mode.

Cisco Discovery Protocol (CDP) exchanges hardware and software device information with its directly connected CDP neighbors. Although this is a useful troubleshooting tool, it would not prevent hosts from communicating with each other. Dynamic Trunking Protocol (DTP) is a Cisco proprietary protocol used to manage automatic trunk negotiation. Disabling DTP would create further issues, as the trunk link would be disabled. Disabling RSTP would not prevent hosts from communicating with each other unless there was a loop involved.

If severity level 2 is configured, only emergency (severity 0), alert (severity 1), and critical (severity 2) messages will be displayed. Cisco syslog messages fall into one of eight levels. The lower the level number, the higher the severity level. The configured severity level indicates the maximum level of severity for which the router should generate syslog messages.

If severity level 5 is configured, emergency (severity 0), alert (severity 1), critical (severity 2), error (severity 3), warning (severity 4), and notification (severity 5) messages will be displayed. If severity level 4 is configured, emergency (severity 0), to warning (severity 4) messages will be displayed. If severity level 3 is configured, emergency (severity 0) to error (severity 3) messages will be displayed.
If severity level 2 is configured, only emergency (severity 0), alert (severity 1), and critical (severity 2) messages will be displayed. Cisco syslog messages fall into one of eight levels. The lower the level number, the higher the severity level. The configured severity level indicates the maximum level of severity for which the router should generate syslog messages.

If severity level 5 is configured, emergency (severity 0), alert (severity 1), critical (severity 2), error (severity 3), warning (severity 4), and notification (severity 5) messages will be displayed. If severity level 4 is configured, emergency (severity 0), to warning (severity 4) messages will be displayed. If severity level 3 is configured, emergency (severity 0) to error (severity 3) messages will be displayed.
If severity level 2 is configured, only emergency (severity 0), alert (severity 1), and critical (severity 2) messages will be displayed. Cisco syslog messages fall into one of eight levels. The lower the level number, the higher the severity level. The configured severity level indicates the maximum level of severity for which the router should generate syslog messages.

If severity level 5 is configured, emergency (severity 0), alert (severity 1), critical (severity 2), error (severity 3), warning (severity 4), and notification (severity 5) messages will be displayed. If severity level 4 is configured, emergency (severity 0), to warning (severity 4) messages will be displayed. If severity level 3 is configured, emergency (severity 0) to error (severity 3) messages will be displayed.

When placing ACLs within a network, standard ACLs should be placed as close to the destination as possible and extended ACLs should be placed as close to the source as possible. Since a standard access list has been configured, it should be applied to the Gi0/0 interface of router R4. In this scenario, this interface will be filtering traffic destined for the 195.168.5.0 network; therefore, it should be configured as an outbound ACL.

None of the other options includes commands that reference interfaces closest to the destination.
When placing ACLs within a network, standard ACLs should be placed as close to the destination as possible and extended ACLs should be placed as close to the source as possible. Since a standard access list has been configured, it should be applied to the Gi0/0 interface of router R4. In this scenario, this interface will be filtering traffic destined for the 195.168.5.0 network; therefore, it should be configured as an outbound ACL.

None of the other options includes commands that reference interfaces closest to the destination.
When placing ACLs within a network, standard ACLs should be placed as close to the destination as possible and extended ACLs should be placed as close to the source as possible. Since a standard access list has been configured, it should be applied to the Gi0/0 interface of router R4. In this scenario, this interface will be filtering traffic destined for the 195.168.5.0 network; therefore, it should be configured as an outbound ACL.

None of the other options includes commands that reference interfaces closest to the destination.

This configuration example demonstrates a dynamic Network Address Translation (NAT) configuration. Dynamic NAT maps an unregistered IPv4 address to a registered IPv4 address from a pool of registered IPv4 addresses (many-to-many). The example translates all source addresses that pass Access Control List (ACL) 1, which means a source address from the 192.168.1.0/24 network, into an address from the pool named net-208. The net-208 pool contains addresses from 171.69.233.209/28 to 171.69.233.222/28.

Because the "overload" keyword is missing from the command-line output PAT and NAT can be excluded as being possible correct options. Static NAT is a mapping of an unregistered IPv4 address to a registered IPv4 address on a one-to-one basis that does not involve an address pool as indicated in the output.
This configuration example demonstrates a dynamic Network Address Translation (NAT) configuration. Dynamic NAT maps an unregistered IPv4 address to a registered IPv4 address from a pool of registered IPv4 addresses (many-to-many). The example translates all source addresses that pass Access Control List (ACL) 1, which means a source address from the 192.168.1.0/24 network, into an address from the pool named net-208. The net-208 pool contains addresses from 171.69.233.209/28 to 171.69.233.222/28.

Because the "overload" keyword is missing from the command-line output PAT and NAT can be excluded as being possible correct options. Static NAT is a mapping of an unregistered IPv4 address to a registered IPv4 address on a one-to-one basis that does not involve an address pool as indicated in the output.
This configuration example demonstrates a dynamic Network Address Translation (NAT) configuration. Dynamic NAT maps an unregistered IPv4 address to a registered IPv4 address from a pool of registered IPv4 addresses (many-to-many). The example translates all source addresses that pass Access Control List (ACL) 1, which means a source address from the 192.168.1.0/24 network, into an address from the pool named net-208. The net-208 pool contains addresses from 171.69.233.209/28 to 171.69.233.222/28.

Because the "overload" keyword is missing from the command-line output PAT and NAT can be excluded as being possible correct options. Static NAT is a mapping of an unregistered IPv4 address to a registered IPv4 address on a one-to-one basis that does not involve an address pool as indicated in the output.

The Cisco Discovery Protocol (CDP) verification commands display information about neighboring devices. The information displayed about neighboring devices includes the neighbor device ID, local interface, hold time value (in seconds), neighbor device capability code, neighbor hardware platform, and neighbor remote port ID. To display information about a specific neighbor, the command string must include the IP address or device ID of the neighbor.

The Cisco Discovery Protocol functionality is enabled by default on all interfaces; however, you can disable this functionality at the device level. To prevent other Cisco Discovery Protocol-capable devices from accessing information about a specific device, you use the no cdp run global configuration command. To disable Cisco Discovery Protocol on an interface, use the no cdp enable command. To enable Cisco Discovery Protocol on an interface, use the cdp enable interface configuration command.
The Cisco Discovery Protocol (CDP) verification commands display information about neighboring devices. The information displayed about neighboring devices includes the neighbor device ID, local interface, hold time value (in seconds), neighbor device capability code, neighbor hardware platform, and neighbor remote port ID. To display information about a specific neighbor, the command string must include the IP address or device ID of the neighbor.

The Cisco Discovery Protocol functionality is enabled by default on all interfaces; however, you can disable this functionality at the device level. To prevent other Cisco Discovery Protocol-capable devices from accessing information about a specific device, you use the no cdp run global configuration command. To disable Cisco Discovery Protocol on an interface, use the no cdp enable command. To enable Cisco Discovery Protocol on an interface, use the cdp enable interface configuration command.
The Cisco Discovery Protocol (CDP) verification commands display information about neighboring devices. The information displayed about neighboring devices includes the neighbor device ID, local interface, hold time value (in seconds), neighbor device capability code, neighbor hardware platform, and neighbor remote port ID. To display information about a specific neighbor, the command string must include the IP address or device ID of the neighbor.

The Cisco Discovery Protocol functionality is enabled by default on all interfaces; however, you can disable this functionality at the device level. To prevent other Cisco Discovery Protocol-capable devices from accessing information about a specific device, you use the no cdp run global configuration command. To disable Cisco Discovery Protocol on an interface, use the no cdp enable command. To enable Cisco Discovery Protocol on an interface, use the cdp enable interface configuration command.

172.17.123.72 is a Class B address. Therefore, it would have 16 bits for the network partition by default. From the subnet mask, we can determine that five bits have been barrowed for subnetting. This leaves 3 bit left over. This gives us a network increment of 8 (2^3=8). In total there would be 32 subnets, with 2046 usable addresses in each. The networks would increment as follows:

172.17.0.0
172.17.8.0
172.17.16.0
172.17.24.0
…
172.17.112.0
172.17.120.0
172.17.128.0

The IP address of 172.17.123.72 belongs to the 172.17.120.0 network. The usable address range of the 172.17.120.0 network is 172.17.120.1 to 172.17.127.254 with 172.17.127.255 being the broadcast address.
172.17.123.72 is a Class B address. Therefore, it would have 16 bits for the network partition by default. From the subnet mask, we can determine that five bits have been barrowed for subnetting. This leaves 3 bit left over. This gives us a network increment of 8 (2^3=8). In total there would be 32 subnets, with 2046 usable addresses in each. The networks would increment as follows:

172.17.0.0
172.17.8.0
172.17.16.0
172.17.24.0
…
172.17.112.0
172.17.120.0
172.17.128.0

The IP address of 172.17.123.72 belongs to the 172.17.120.0 network. The usable address range of the 172.17.120.0 network is 172.17.120.1 to 172.17.127.254 with 172.17.127.255 being the broadcast address.
172.17.123.72 is a Class B address. Therefore, it would have 16 bits for the network partition by default. From the subnet mask, we can determine that five bits have been barrowed for subnetting. This leaves 3 bit left over. This gives us a network increment of 8 (2^3=8). In total there would be 32 subnets, with 2046 usable addresses in each. The networks would increment as follows:

172.17.0.0
172.17.8.0
172.17.16.0
172.17.24.0
…
172.17.112.0
172.17.120.0
172.17.128.0

The IP address of 172.17.123.72 belongs to the 172.17.120.0 network. The usable address range of the 172.17.120.0 network is 172.17.120.1 to 172.17.127.254 with 172.17.127.255 being the broadcast address.

When sticky learning is configured on an interface, the interface converts dynamically learned addresses to "sticky secure" addresses. This feature adds the dynamically learned addresses to the running configuration as if they were statically configured using the switchport port-security mac-address command. Sticky-learned addresses do not age out.

Using a combination of dynamic and static implementations, you can choose to specify some of the permitted MAC addresses and let the switch learn the rest of the permitted MAC addresses. This combination would not meet the requirements because the dynamically learned addresses can age out and static implementations require you to manually enter addresses.
When sticky learning is configured on an interface, the interface converts dynamically learned addresses to "sticky secure" addresses. This feature adds the dynamically learned addresses to the running configuration as if they were statically configured using the switchport port-security mac-address command. Sticky-learned addresses do not age out.

Using a combination of dynamic and static implementations, you can choose to specify some of the permitted MAC addresses and let the switch learn the rest of the permitted MAC addresses. This combination would not meet the requirements because the dynamically learned addresses can age out and static implementations require you to manually enter addresses.
When sticky learning is configured on an interface, the interface converts dynamically learned addresses to "sticky secure" addresses. This feature adds the dynamically learned addresses to the running configuration as if they were statically configured using the switchport port-security mac-address command. Sticky-learned addresses do not age out.

Using a combination of dynamic and static implementations, you can choose to specify some of the permitted MAC addresses and let the switch learn the rest of the permitted MAC addresses. This combination would not meet the requirements because the dynamically learned addresses can age out and static implementations require you to manually enter addresses.

RFC 4291 specifies 2000::/3 to be global unicast address space that the IANA may allocate to the Regional Internet Registries (RIRs). A global unicast address is an IPv6 address from the global unicast prefix. The structure of global unicast addresses enables the aggregation of routing prefixes, which limits the number of routing table entries in the global routing table. Global unicast addresses that are used on links are aggregated upward through organizations and eventually to the ISPs. The loopback address is 0:0:0:0:0:0:0:1, which is normally expressed as ::1. Link-local addresses refer only to a particular physical link. Link-local addresses typically begin with "FE80".

A multicast address identifies a group of interfaces. Traffic that is sent to a multicast address is sent to multiple destinations at the same time. An interface may belong to any number of multicast groups. The IPv6 unicast address space encompasses the entire IPv6 address range, with the exception of FF00::/8 (1111 1111), which is used for multicast addresses.
RFC 4291 specifies 2000::/3 to be global unicast address space that the IANA may allocate to the Regional Internet Registries (RIRs). A global unicast address is an IPv6 address from the global unicast prefix. The structure of global unicast addresses enables the aggregation of routing prefixes, which limits the number of routing table entries in the global routing table. Global unicast addresses that are used on links are aggregated upward through organizations and eventually to the ISPs. The loopback address is 0:0:0:0:0:0:0:1, which is normally expressed as ::1. Link-local addresses refer only to a particular physical link. Link-local addresses typically begin with "FE80".

A multicast address identifies a group of interfaces. Traffic that is sent to a multicast address is sent to multiple destinations at the same time. An interface may belong to any number of multicast groups. The IPv6 unicast address space encompasses the entire IPv6 address range, with the exception of FF00::/8 (1111 1111), which is used for multicast addresses.
RFC 4291 specifies 2000::/3 to be global unicast address space that the IANA may allocate to the Regional Internet Registries (RIRs). A global unicast address is an IPv6 address from the global unicast prefix. The structure of global unicast addresses enables the aggregation of routing prefixes, which limits the number of routing table entries in the global routing table. Global unicast addresses that are used on links are aggregated upward through organizations and eventually to the ISPs. The loopback address is 0:0:0:0:0:0:0:1, which is normally expressed as ::1. Link-local addresses refer only to a particular physical link. Link-local addresses typically begin with "FE80".

A multicast address identifies a group of interfaces. Traffic that is sent to a multicast address is sent to multiple destinations at the same time. An interface may belong to any number of multicast groups. The IPv6 unicast address space encompasses the entire IPv6 address range, with the exception of FF00::/8 (1111 1111), which is used for multicast addresses.

Static Network Address Translation (NAT) is manually configured. It maps an unregistered IPv4 address to a registered IPv4 address (one-to-one).

For more information on the commands you would need to enter to create a static address translation, please refer to the |h %5coutput%5ct14%5cmisc%5c100105eo418a.html additional explanation.

Cisco Express Forwarding (CEF) is the most recent and preferred Cisco IOS packet-forwarding mechanism. It incorporates the best of the previous switching mechanisms such as fast switching and process switching. The generation of cache table entries is not packet-triggered, but change-triggered. When something changes in the network topology, the change is also reflected in the cache table. This makes Cisco Express Forwarding the fastest forwarding mechanism and the preferred choice.

Hop count is a metric, not a packet-forwarding mechanism. Hop count is the number of routers that a packet must travel through before reaching its destination.
Cisco Express Forwarding (CEF) is the most recent and preferred Cisco IOS packet-forwarding mechanism. It incorporates the best of the previous switching mechanisms such as fast switching and process switching. The generation of cache table entries is not packet-triggered, but change-triggered. When something changes in the network topology, the change is also reflected in the cache table. This makes Cisco Express Forwarding the fastest forwarding mechanism and the preferred choice.

Hop count is a metric, not a packet-forwarding mechanism. Hop count is the number of routers that a packet must travel through before reaching its destination.
Cisco Express Forwarding (CEF) is the most recent and preferred Cisco IOS packet-forwarding mechanism. It incorporates the best of the previous switching mechanisms such as fast switching and process switching. The generation of cache table entries is not packet-triggered, but change-triggered. When something changes in the network topology, the change is also reflected in the cache table. This makes Cisco Express Forwarding the fastest forwarding mechanism and the preferred choice.

Hop count is a metric, not a packet-forwarding mechanism. Hop count is the number of routers that a packet must travel through before reaching its destination.

If many CRC errors are present, there is too much noise on the link and you should inspect the cable for damage and length. You should also search for and eliminate noise sources, if possible.

Using half duplex normally results in collisions. Collisions in half duplex operations are normal, and you should not be concerned about them as long as you are pleased with the half-duplex operations. A late collision is a collision that occurs after the preamble is transmitted. Late collisions occur when you have serious problems in a switched network, such as duplex misconfiguration. If the line protocol and the interface are both down, a cable is not attached or some other interface problem exists.
If many CRC errors are present, there is too much noise on the link and you should inspect the cable for damage and length. You should also search for and eliminate noise sources, if possible.

Using half duplex normally results in collisions. Collisions in half duplex operations are normal, and you should not be concerned about them as long as you are pleased with the half-duplex operations. A late collision is a collision that occurs after the preamble is transmitted. Late collisions occur when you have serious problems in a switched network, such as duplex misconfiguration. If the line protocol and the interface are both down, a cable is not attached or some other interface problem exists.
If many CRC errors are present, there is too much noise on the link and you should inspect the cable for damage and length. You should also search for and eliminate noise sources, if possible.

Using half duplex normally results in collisions. Collisions in half duplex operations are normal, and you should not be concerned about them as long as you are pleased with the half-duplex operations. A late collision is a collision that occurs after the preamble is transmitted. Late collisions occur when you have serious problems in a switched network, such as duplex misconfiguration. If the line protocol and the interface are both down, a cable is not attached or some other interface problem exists.

Static routes are routes that are manually entered into a routing table by an administrator. Static routes specify the path that packets take when moving between a source and a destination and are commonly used when routing from a network to a stub network. A static route can be configured by using the ip route command. The assignment of a static route to reach the stub network 172.16.1.0 is proper for Router A because there is only one way to reach that network. When configuring a static route, you need to include the network address and subnet mask of the remote network, along with the IP address of the next-hop router or the exit interface of the router you are configuring. To configure a static route using the next-hop router, you can use either of the following commands:

RouterA(config)#ip route 172.16.1.0 255.255.255.0 172.16.2.1

Or

RouterA(config)#ip route 172.16.1.0 255.255.255.0 serial0/0/0
Static routes are routes that are manually entered into a routing table by an administrator. Static routes specify the path that packets take when moving between a source and a destination and are commonly used when routing from a network to a stub network. A static route can be configured by using the ip route command. The assignment of a static route to reach the stub network 172.16.1.0 is proper for Router A because there is only one way to reach that network. When configuring a static route, you need to include the network address and subnet mask of the remote network, along with the IP address of the next-hop router or the exit interface of the router you are configuring. To configure a static route using the next-hop router, you can use either of the following commands:

RouterA(config)#ip route 172.16.1.0 255.255.255.0 172.16.2.1

Or

RouterA(config)#ip route 172.16.1.0 255.255.255.0 serial0/0/0
Static routes are routes that are manually entered into a routing table by an administrator. Static routes specify the path that packets take when moving between a source and a destination and are commonly used when routing from a network to a stub network. A static route can be configured by using the ip route command. The assignment of a static route to reach the stub network 172.16.1.0 is proper for Router A because there is only one way to reach that network. When configuring a static route, you need to include the network address and subnet mask of the remote network, along with the IP address of the next-hop router or the exit interface of the router you are configuring. To configure a static route using the next-hop router, you can use either of the following commands:

RouterA(config)#ip route 172.16.1.0 255.255.255.0 172.16.2.1

Or

RouterA(config)#ip route 172.16.1.0 255.255.255.0 serial0/0/0

Cisco IOS Software on a Cisco switch has various configuration modes that are hierarchically structured. The major modes are user EXEC, privileged EXEC, global configuration, and interface configuration. You can only access a lower-level mode from a higher-level mode due to its hierarchal layout. For example, in order to access global configuration mode, you must be in the privileged EXEC mode. Each mode is used to accomplish particular tasks and has a specific set of commands that are available in that mode. To use the mac-address-table aging-time command, you must be in global configuration mode. This is represented by the Router(config)# prompt.
Cisco IOS Software on a Cisco switch has various configuration modes that are hierarchically structured. The major modes are user EXEC, privileged EXEC, global configuration, and interface configuration. You can only access a lower-level mode from a higher-level mode due to its hierarchal layout. For example, in order to access global configuration mode, you must be in the privileged EXEC mode. Each mode is used to accomplish particular tasks and has a specific set of commands that are available in that mode. To use the mac-address-table aging-time command, you must be in global configuration mode. This is represented by the Router(config)# prompt.
Cisco IOS Software on a Cisco switch has various configuration modes that are hierarchically structured. The major modes are user EXEC, privileged EXEC, global configuration, and interface configuration. You can only access a lower-level mode from a higher-level mode due to its hierarchal layout. For example, in order to access global configuration mode, you must be in the privileged EXEC mode. Each mode is used to accomplish particular tasks and has a specific set of commands that are available in that mode. To use the mac-address-table aging-time command, you must be in global configuration mode. This is represented by the Router(config)# prompt.

The restrict violation mode also drops packets with unknown source addresses until you remove enough secure MAC addresses to drop below the maximum value. However, it also generates a log message and causes the security violation counter to increment.

The protect violation mode drops packets with unknown source addresses until you remove enough secure MAC addresses to drop below the maximum value. It does not keep a running count of packets dropped. The shutdown violation mode puts the interface into an error-disabled state immediately. Error-disabled is not a port violation mode, but a state that is caused from the shutdown violation mode.
The restrict violation mode also drops packets with unknown source addresses until you remove enough secure MAC addresses to drop below the maximum value. However, it also generates a log message and causes the security violation counter to increment.

The protect violation mode drops packets with unknown source addresses until you remove enough secure MAC addresses to drop below the maximum value. It does not keep a running count of packets dropped. The shutdown violation mode puts the interface into an error-disabled state immediately. Error-disabled is not a port violation mode, but a state that is caused from the shutdown violation mode.
The restrict violation mode also drops packets with unknown source addresses until you remove enough secure MAC addresses to drop below the maximum value. However, it also generates a log message and causes the security violation counter to increment.

The protect violation mode drops packets with unknown source addresses until you remove enough secure MAC addresses to drop below the maximum value. It does not keep a running count of packets dropped. The shutdown violation mode puts the interface into an error-disabled state immediately. Error-disabled is not a port violation mode, but a state that is caused from the shutdown violation mode.

A loopback interface is a virtual interface that resides on a router. It is not connected to any other device. Loopback interfaces are very useful because they will never go "down," unless the entire router goes down. This helps in managing routers because there will always be at least one active interface on the routers-the loopback interface. To create a loopback interface, all you need to do is enter the configuration mode for the interface. Optionally, you may add an IP address. The range of addresses that are reserved for loopback addresses are 127.0.0.1 to 127.255.255.255.0
A loopback interface is a virtual interface that resides on a router. It is not connected to any other device. Loopback interfaces are very useful because they will never go "down," unless the entire router goes down. This helps in managing routers because there will always be at least one active interface on the routers-the loopback interface. To create a loopback interface, all you need to do is enter the configuration mode for the interface. Optionally, you may add an IP address. The range of addresses that are reserved for loopback addresses are 127.0.0.1 to 127.255.255.255.0
A loopback interface is a virtual interface that resides on a router. It is not connected to any other device. Loopback interfaces are very useful because they will never go "down," unless the entire router goes down. This helps in managing routers because there will always be at least one active interface on the routers-the loopback interface. To create a loopback interface, all you need to do is enter the configuration mode for the interface. Optionally, you may add an IP address. The range of addresses that are reserved for loopback addresses are 127.0.0.1 to 127.255.255.255.0