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Ethernet Technologies

Subject : it-skills

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. What are the basic operations that a frame undergoes as it passes through a multilayer switch?
Ingress queueing; Destination MAC lookup (CAM); Destination IP lookup (FIB); Security ACL lookup (TCAM); QoS ACL lookup (TCAM); Layer 3 packet rewrite; Egress queueing
Switch(config-if)#no ip route-cache cef
25 metres
Switch(config)#errdisable detect cause udld

2. What is the timer range for automatic re-enabling of error-disabled ports?
Full duplex if only one of the two stacking connectors is used; Half duplex over a shared bus if if both connectors are used
From 30 seconds to 86 -400 seconds (24 hours)
The Layer 3 forwarding engine
1000BASE-CX - 1000BASE-T - 1000-BASE-SX - 1000-BASE-LX/LH and 1000-BASE-ZX

3. What is the default duplex mode of a 10 Mbps Ethernet interface?
Switch#show ip cef {interface} [detail]
When the Spanning Tree Protocol (STP) has put the switch port in learning or forwarding state
FIB with adjacency table
Half duplex

4. What is CEF?
Bundling together two to eight full duplex Fast Ethernet links to act as a single physical link
40 km
Routing table and ARP table
Cisco Express Forwarding

5. What are the names of CEF optimisation techniques using specialised forwarding hardware?
Accelerated CEF (aCEF) and Distributed CEF (dCEF)
LOU registers
LC - MT-RJ or RJ-45
Switch(config)#errdisable detect cause loopback

6. When are mode-conditioning patch leads required with 1000BASE-LX/LH transceivers?
Layer 2 destination address changed to next-hop MAC address; Layer 2 source address changed to outbound interface MAC address; Layer 3 TTL decremented by 1; Layer 3 IP checksum recalculated; Layer 2 frame checksum recalculated
Switch#show errdisable recovery
Through exchange of information - which means that for one end to successfully negotiate duplex mode the other end must also be set to autonegotiate
With MMF cables shorter than 100 metres (to prevent over-driving the far-end receiver) and with MMF cables longer than 300 metres (to lessen the effect of differential mode delay)

7. Enables error-disable when trunking encapsulation is flapping from one type to another
Switch(config)#errdisable detect cause dtp-flap
Tunnel
In TCAM Value entries
IEEE 802.3ae

8. What is the TCAM Value and Mask for an IGMP access list?
Switch(config)#errdisable detect cause dtp-flap
Source IP (/32); Destination IP (/32); Protocol (/16); IP ToS (/8); IGMP message type (/8)
Switched virtual interface (SVI)
Down - static access - trunk or tunnel

9. How are MAC addresses shown in the detailed output from the CEF adjacency table?
SC or MT-RJ
Cabling specification for 10 Mbps Ethernet over Unshielded Twisted Pair (UTP) cabling
Adjacent MAC address (6 octets); Layer 3 engine MAC address (6 octets); EtherType (2 octets)
SVI

10. What is EMI?
Full duplex only
Electromagnetic Interference
Switch(config)#default interface {interface}
Native routed interface

11. How do Layer 2 switches provide isolation between hosts?
Trunk
Per port collision domains; Full duplex mode; Dedicated bandwidth; Error detection; Broadcast thresholds; Intelligent filtering and forwarding
A switch port that has been shut down automatically due to a serious error condition
Switch(config)#errdisable detect cause vmps

12. What is ANSI?
American National Standards Institute
Switch(config)#errdisable detect cause loopback
Carrier Sense Multiple Access Collision Detection
Value - Mask - and Result (VMR)

13. What is the operational mode of a switch port that carries traffic for multiple VLANs?
Layer 3 routing information builds and pre-populates a single database of the entire network topology; All table lookups are performed in hardware with the longest matching destination used in forwarding
Switch(config)#errdisable detect cause dhcp-rate-limit
Electromagnetic Interference
Trunk

14. What function is performed by the Switching Database Manager (SDM)?
With MMF cables shorter than 100 metres (to prevent over-driving the far-end receiver) and with MMF cables longer than 300 metres (to lessen the effect of differential mode delay)
Switch#show ip cef {interface} [detail]
Partition and tune the TCAM on some Catalyst switches into areas for different functions
Full duplex

15. What is the DTP negotiation mode of a switch port configured as trunk?
On
Trunk
Half duplex
The Layer 3 engine

16. Enables error-disable for errors with dynamic ARP inspection
Switch(config-if)#no ip route-cache cef
ARP requests and replies; IP packets requiring an ICMP response; IP broadcasts to be relayed; Routing protocol updates; CDP packets; Packets needing encryption; Packets triggering NAT; Other non-IP packets
Switch(config)#errdisable detect cause arp-inspection
Switch(config)#errdisable detect cause security-violation

17. Specifies the timer for automatic re-enabling of error-disabled ports
Switch(config)#errdisable recovery interval {seconds}
Switch#show cef not-cef-switched
Off
40 km

18. What portion of the FIB contains the Layer 3 next-hop addresses for each entry together with the corresponding Layer 2 information?
Switch(config)#errdisable detect cause gbic-invalid
The adjacency table
Switch#show interfaces status err-disabled
Switch#show adjacency [{interface}] [summary | detail]

19. What is the maximum cabling distance for 1000BASE-CX?
25 metres
Carrier Sense Multiple Access Collision Detection
Switch(config)#errdisable detect cause udld
Slow response times - low throughput - runts and other input errors on the switch ports

20. What CEF adjacency is used to discard packets because of access list or other policy action?
Switch#show mac address-table [address {mac-address}] [interface {interface}] [vlan {vlan}]
Listen to the first packet and put its resulting destination in the MLS cache; Route subsequent packets in the same flow based on the MLS cache
100BASE-TX - 100BASE-T2 - 100BASE-T4 and 100-BASE-FX
The Discard adjacency

21. Selects an interface-range macro and enters interface configuration mode
Security and QoS ACLs
Carrier Sense Multiple Access Collision Detection
Switch#show interfaces {interface} switchport
Switch(config)#interface range macro {name}

22. What is the administrative mode of a switch port that carries traffic for multiple VLANs?
Trunk or dynamic
Switch(config-if)#no switchport
Switch(config)#errdisable detect cause ilpower
Switch(config-if)#description {string}

23. What changes are made to packets by the CEF packet rewrite engine just before forwarding?
Fast Ethernet over 2 pairs EIA/TIA Category 3 - 4 - 5 UTP
Gigabit Ethernet over 1 pair 8 or 9 micron SMF (1550 nm laser)
Layer 2 destination address changed to next-hop MAC address; Layer 2 source address changed to outbound interface MAC address; Layer 3 TTL decremented by 1; Layer 3 IP checksum recalculated; Layer 2 frame checksum recalculated
ANSI X3T11 FibreChannel

24. What is CSMA/CD?
Carrier Sense Multiple Access Collision Detection
When the Spanning Tree Protocol (STP) has put the switch port in learning or forwarding state
Creating the VLAN
Source MAC address; Port of arrival; VLAN; Time stamp

25. Enables error-disable for conditions that trigger unicast flood blocking on a port
Half duplex
Switch(config)#errdisable detect cause unicast-flood
Entry not in FIB; FIB table full; IP TTL expired; MTU exceeded; ICMP redirect; Unsupported encapsulation; Tunnelled packets requiring compression or encryption; Access list with 'log' option; NAT must be performed
Switch#show interfaces status err-disabled

26. What is the default duplex mode of a Gigabit Ethernet interface?
Numeric values that represent what action to take after the TCAM lookup occurs
Switch(config-if)#switchport access vlan {vlan}
Multilayer Switching
Full duplex

27. Displays interface configuration information
Full duplex only
Switch#show running-config interface {interface}
In TCAM Value entries
Switch(config-if)#duplex {auto | full | half}

28. What is 100BASE-T4?
When one station transmits at the same time as another on a shared medium
Incomplete adjacency; Incomplete ARP resolution; Unsupported packet features; ICMP redirect; Packets destined to the router itself; IP options present; Access list evaluation failure; Fragmentation failure
Fast Ethernet over 4 pairs EIA/TIA Category 3 - 4 - 5 UTP
Trunk

29. How is link duplex mode determined on Fast Ethernet links configured to autonegotiate?
1 -2 on one end with 3 -6 on the other end
550 metres for 50 or 62.5 micron MMF; 10 km for 9 micron SMF
Switch#show running-config interface {interface}
Through exchange of information - which means that for one end to successfully negotiate duplex mode the other end must also be set to autonegotiate

30. What fields are rewritten in hardware before a Layer 3 packet is switched to the to egress queue of a multilayer switch?
Cabling specification for 10 Mbps Ethernet over Unshielded Twisted Pair (UTP) cabling
Half duplex
Layer 2 source and destination MAC addresses; Layer 3 Time-To-Live (TTL) value and header checksum
Route caching and topology based

31. What are the common PMD types for 10 Gigabit Ethernet?
American National Standards Institute
ANSI X3T11 FibreChannel
IEEE 802.3z
10GBASE-SR/SW - 10GBASE-LR/LW - 10GBASE-ER/EW - 10GBASE-LX4/LW4 - 10GBASE-CX4

32. How does topology based switching work?
Static access or dynamic
Layer 3 routing information builds and pre-populates a single database of the entire network topology; All table lookups are performed in hardware with the longest matching destination used in forwarding
Bundling together two to eight full duplex Fast Ethernet links to act as a single physical link
In TCAM Value entries

33. What two IOS software components are involved in TCAM operation?
10 Gigabit Ethernet over 50 or 62.5 micron MMF or 9 micron SMF (1300 nm WWDM laser)
Switch#show mac address-table count [address {mac-address}] [interface {interface}] [vlan {vlan}]
Feature Manager (FM) and Switching Database Manager (SDM)
Switch(config)#errdisable recovery interval {seconds}

34. Disables CEF operation globally
LAN PHY and WAN PHY
Switch(config)#no ip cef
LC - MT-RJ or RJ-45
They are dropped (ARP throttling)

35. What are the basic operations that a frame undergoes as it passes through a Layer 2 switch?
SC fibre optic or RJ-45 UTP
Ingress queueing; Destination MAC lookup (CAM); Security ACL lookup (TCAM); QoS ACL lookup (TCAM); Egress queueing
Entry not in FIB; FIB table full; IP TTL expired; MTU exceeded; ICMP redirect; Unsupported encapsulation; Tunnelled packets requiring compression or encryption; Access list with 'log' option; NAT must be performed
Partition and tune the TCAM on some Catalyst switches into areas for different functions

36. What is the standard for 10 Gigabit Ethernet (10GbE)?
IEEE 802.3ae
Source MAC address; Port of arrival; VLAN; Time stamp
CEF glean
SVI

37. What is CAM?
Down - static access - trunk or tunnel
Electromagnetic Interference
A three-fold combination of 0 - 1 and X (don't care)
Content-Addressable Memory

38. What is full duplex operation?
Enable error-disable for all possible causes
Distributed CEF (dCEF)
Stations can transmit and receive at the same time because switched Ethernet removes the possibility of collisions
Switch(config)#errdisable detect cause dhcp-rate-limit

39. What is TCAM overflow?
Gigabit Ethernet over 1 pair 50 or 62.5 micron MMF or 9 micron SMF (1300 nm laser)
Interconnecting with existing Synchronous Optical Network (SONET) or Synchronous Digital Hierarchy (SDH) networks
When there are more access list entries and Layer 4 operations than available Mask/Value and LOU entries
UTP Fast Ethernet and Gigabit Ethernet

40. What denotes the number of times a CEF entry has been updated since the CEF table was created?
The CEF entry version number
300 metres for 50 or 62.5 micron MMF; 10 km for 9 micron SMF
Collision domain
Gigabit Ethernet over 1 pair 8 or 9 micron SMF (1550 nm laser)

41. How is the TCAM organised?
In TCAM Value entries
66-300 metres for 50 micron MMF; 33 metres for 62.5 micron MMF
The switch port falls back to default setting of half duplex
By Mask/Value - where each unique mask has eight value patterns associated with it

42. What are the operational modes of a Layer 2 switched interface?
Gigabit Ethernet over 1 pair Shielded Twisted Pair (STP) cabling
Down - static access - trunk or tunnel
Manually by administratively disabling and re-enabling the port
Switch#show ip cef

43. What is the operational mode of a switch port that carries transparent Layer 2 VPNs?
Tunnel
S = Short; L = Long; E = Extra-long
Incomplete adjacency; Incomplete ARP resolution; Unsupported packet features; ICMP redirect; Packets destined to the router itself; IP options present; Access list evaluation failure; Fragmentation failure
Source IP (/32) - Destination IP (/32) - Protocol (/16) - IP ToS (/8) - Source port (/16) - Source operator (/4) - Destination port (/16) - Destination operator (/4)

44. What is 10BASE-T?
Cabling specification for 10 Mbps Ethernet over Unshielded Twisted Pair (UTP) cabling
Tunnel
Ternary Content-Addressable Memory
10 Gigabit Ethernet over 9 micron SMF (1310 nm serial laser)

45. When can a switch start to learn source MAC addresses on incoming ports?
When the Spanning Tree Protocol (STP) has put the switch port in learning or forwarding state
The Layer 3 forwarding engine
10 Gigabit Ethernet over 50 or 62.5 micron MMF (850 nm serial laser)
Switch(config)#errdisable detect cause pagp-flap

46. What is the default timer for automatic re-enabling of error-disabled ports?
Switch(config)#interface range macro {name}
300 seconds
Switch(config)#mac address-table aging-time {seconds}
Creating the VLAN

47. What are the symptoms of a duplex setting mismatch between two ends of a link?
Trunk or dynamic
When there are more access list entries and Layer 4 operations than available Mask/Value and LOU entries
Slow response times - low throughput - runts and other input errors on the switch ports
Source IP (/32); Destination IP (/32); Protocol (/16); IP ToS (/8)

48. What is 1000BASE-LX/LH?
Gigabit Ethernet over 1 pair 50 or 62.5 micron MMF or 9 micron SMF (1300 nm laser)
Listen to the first packet and put its resulting destination in the MLS cache; Route subsequent packets in the same flow based on the MLS cache
Switch(config-if)#shutdown
550 metres for 50 or 62.5 micron MMF; 10 km for 9 micron SMF

49. What is the maximum cabling distance for 10GBASE-CX4?
SVI
Flooding a frame with unknown destination MAC address out all ports assigned to the source port VLAN except the source port itself
15 metres
10 Gigabit Ethernet over 9 micron SMF (1310 nm serial laser)

50. What is 10GBASE-X?
Switch(config)#errdisable detect cause dtp-flap
Collision domain
Process the first packet in a traffic flow to determine the destination
Cabling specifications for 10 Gigabit Ethernet