1. portfast is a method of disabling STP on a switch port.
2. STP switch port states: Blocking, listening, learning, forwarding, disabled
3. RSTP is interoperable with legacy STP, but some features are lost when some switches are running
STP. e.g. Fast convergence.
4. Flow Control and Congestive Feedback are functions of the Network layer. Bridges operate at the data Link layer so these responsibilities fall to the end devices in a bridged environment.
5. Fragment Free is also referred to as Modified Cut-Through. It is the default mode used by Cisco Catalyst 1900 series switches. This switching method is the same as with Cut-Through except the switch will check the first 64 bytes of every frame received as this is where the vast majority of errors occur within a frame.
6. To erase the startup configuration use the following command:
Router#erase startup-config or Router#erase startup
7. The various states of an interface:
8. To turn off CDP use the no cdp run command from the global configuration mode.
9. IGRP sends its routing table to its neighbors every 90 seconds. IGRP uses an invalid timer to mark a route as invalid after 270 seconds (three times the update timer). IGRP uses a flush timer to remove a route from the routing table (default flush timer is 630 seconds, seven times the update period).
10. A switched network can be described as a flat network because broadcasts are transmitted to every device.
11. Cisco's proprietary VLAN tagging (ISL) has a maximum frame size of 1548 bytes.
IEEE 802.1q VLAN tagging has a maximum frame size of 1522 bytes.
12. If you wish to remove an access-list, you use the no access-list (list #) command
13. HDLC and PPP are WAN encapsulations that are typically used on a leased line
14. 802.11a operates in the 5GHz band with a data rate of up to 54Mbps and is immune to interference from other devices operating in the 2.4GHz spectrum.
15. Cisco routers are DTEs by default (Data Terminal Equipment). The DCE (Data Circuit-Terminating Equipment) at the other end of the connection must supply a clock rate to the DTE. The interface needs clock rate when it is DCE.
16. IP provides no form of error correction/ acknowledgments.
2. STP switch port states: Blocking, listening, learning, forwarding, disabled
3. RSTP is interoperable with legacy STP, but some features are lost when some switches are running
STP. e.g. Fast convergence.
4. Flow Control and Congestive Feedback are functions of the Network layer. Bridges operate at the data Link layer so these responsibilities fall to the end devices in a bridged environment.
5. Fragment Free is also referred to as Modified Cut-Through. It is the default mode used by Cisco Catalyst 1900 series switches. This switching method is the same as with Cut-Through except the switch will check the first 64 bytes of every frame received as this is where the vast majority of errors occur within a frame.
6. To erase the startup configuration use the following command:
Router#erase startup-config or Router#erase startup
7. The various states of an interface:
Ethernet0 is up, line protocol is up - The interface is functioning correctly.
Ethernet0 is down, line protocol is down - This message usually represents a physical interface problem. The cable may be disconnected. This can also occur if this interface is connected to another router whose interface has been shut down.
Ethernet0 is up, line protocol is down - The Physical layer connectivity is not the issue. The line protocol being down is either a clocking issue (keepalives) or a mismatch of the frame types being used on connected devices.
Ethernet0 is administratively down, line protocol is down - The interface has been manually shutdown using the shutdown command.
Ethernet0 is down, line protocol is down - This message usually represents a physical interface problem. The cable may be disconnected. This can also occur if this interface is connected to another router whose interface has been shut down.
Ethernet0 is up, line protocol is down - The Physical layer connectivity is not the issue. The line protocol being down is either a clocking issue (keepalives) or a mismatch of the frame types being used on connected devices.
Ethernet0 is administratively down, line protocol is down - The interface has been manually shutdown using the shutdown command.
8. To turn off CDP use the no cdp run command from the global configuration mode.
9. IGRP sends its routing table to its neighbors every 90 seconds. IGRP uses an invalid timer to mark a route as invalid after 270 seconds (three times the update timer). IGRP uses a flush timer to remove a route from the routing table (default flush timer is 630 seconds, seven times the update period).
10. A switched network can be described as a flat network because broadcasts are transmitted to every device.
11. Cisco's proprietary VLAN tagging (ISL) has a maximum frame size of 1548 bytes.
IEEE 802.1q VLAN tagging has a maximum frame size of 1522 bytes.
12. If you wish to remove an access-list, you use the no access-list (list #) command
13. HDLC and PPP are WAN encapsulations that are typically used on a leased line
14. 802.11a operates in the 5GHz band with a data rate of up to 54Mbps and is immune to interference from other devices operating in the 2.4GHz spectrum.
15. Cisco routers are DTEs by default (Data Terminal Equipment). The DCE (Data Circuit-Terminating Equipment) at the other end of the connection must supply a clock rate to the DTE. The interface needs clock rate when it is DCE.
16. IP provides no form of error correction/ acknowledgments.
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