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Ethernet Technologies

Subject : it-skills

Instructions:

Answer 50 questions in 15 minutes.
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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 operational modes of a Layer 2 switched interface?
American National Standards Institute
A name assigned to a ranges of interfaces
Down - static access - trunk or tunnel
Ingress queueing; Destination MAC lookup (CAM); Destination IP lookup (FIB); Security ACL lookup (TCAM); QoS ACL lookup (TCAM); Layer 3 packet rewrite; Egress queueing

2. What are the letters used with 10GBASE-X two-letter suffixes to specify the PHY type?
R = LAN PHY; W = WAN PHY
S = Short; L = Long; E = Extra-long
Switch#show interfaces {interface}
100BASE-TX - 100BASE-T2 - 100BASE-T4 and 100-BASE-FX

3. Enables error-disable when a link is seen to be unidirectional
Switch(config)#errdisable detect cause storm-control
Switch(config)#errdisable detect cause udld
Switch#show interfaces {interface}
Switch(config)#define interface-range {macro-name} {type} {module}/{number} [- {number}] [ - {type} {module}/{number} ...]

4. What is the maximum cabling distance for 1000BASE-SX?
66-300 metres for 50 micron MMF; 33 metres for 62.5 micron MMF
Layer 2 source and destination MAC addresses; Layer 3 Time-To-Live (TTL) value and header checksum
275 metres for 62.5 micron MMF; 550 metres for 50 micron MMF
UTP Fast Ethernet and Gigabit Ethernet

5. What information is stored in TCAM?
Fast Ethernet over 62.5/125 micron multimode fibre (MMF) or 9 micron singlemode fibre (SMF)
Security and QoS ACLs
The Discard adjacency
On

6. What is EMI?
Electromagnetic Interference
Static access or dynamic
Static access or trunk
Flooding a frame with unknown destination MAC address out all ports assigned to the source port VLAN except the source port itself

7. What is the administrative mode of a switch port that uses DTP to negotiate its operational mode?
Dynamic
Switch(config)#errdisable detect cause dtp-flap
Switch#show running-config interface {interface}
Switch(config)#interface range {type}{module}/{number} [- {number}] [ - {type}{module}/{number} ...]

8. What is the role of a Route Processor (RP) in first generation MLS?
American National Standards Institute
Process the first packet in a traffic flow to determine the destination
FIB with adjacency table
Switched virtual interface (SVI)

9. What are the duplex modes of a GigaStack GBIC?
The CEF epoch number
Switch(config)#default interface {interface}
A switch port that has been shut down automatically due to a serious error condition
Full duplex if only one of the two stacking connectors is used; Half duplex over a shared bus if if both connectors are used

10. What is the operational mode of a switch port that is a member of one VLAN?
IEEE 802.3ae
10 Gigabit Ethernet over 9 micron SMF (1550 nm serial laser)
Switch(config)#errdisable detect cause pagp-flap
Static access

11. What is 1000BASE-T?
Switch#show adjacency [{interface}] [summary | detail]
Gigabit Ethernet over 4 pairs EIA/TIA Category 5 UTP
IEEE 802.3ae
When there are more access list entries and Layer 4 operations than available Mask/Value and LOU entries

12. What are runts?
S = Short; L = Long; E = Extra-long
Switch(config)#errdisable detect cause pagp-flap
Partition and tune the TCAM on some Catalyst switches into areas for different functions
Packets that have been truncated before they were fully received

13. What happens to subsequent packets destined for FIB entries in CEF glean state?
They are dropped (ARP throttling)
Interconnecting switches in a campus network
10 Gigabit Ethernet over 9 micron SMF (1310 nm serial laser)
Interconnecting with existing Synchronous Optical Network (SONET) or Synchronous Digital Hierarchy (SDH) networks

14. What is CSMA/CD?
Carrier Sense Multiple Access Collision Detection
1000BASE-T full duplex followed by 1000BASE-T half duplex
Security and QoS ACLs
Switch(config)#errdisable detect cause psecure-violation

15. What technology was merged into the IEEE 802.3 Ethernet standard to create Gigabit Ethernet?
ANSI X3T11 FibreChannel
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)
When one station transmits at the same time as another on a shared medium
10 Gigabit Ethernet over 9 micron SMF (1310 nm serial laser)

16. What is the maximum cabling distance for 10GBASE-SR/SW?
10GBASE-SR/SW - 10GBASE-LR/LW - 10GBASE-ER/EW - 10GBASE-LX4/LW4 - 10GBASE-CX4
Switch(config)#interface {type}{module}/{number}
Switch(config-if)#shutdown
66-300 metres for 50 micron MMF; 33 metres for 62.5 micron MMF

17. Changes an interface to a layer 3 interface and erases all layer 2 interface configurations
Switch#show ip cef
Switch(config-if)#no switchport
10 Gigabit Ethernet over 9 micron SMF (1310 nm serial laser)
When there are more access list entries and Layer 4 operations than available Mask/Value and LOU entries

18. How does topology based switching work?
Security and QoS ACLs
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
275 metres for 62.5 micron MMF; 550 metres for 50 micron MMF
Switch(config)#errdisable detect cause {all | {cause-name}}

19. What CEF optimisation technique cache FIB entries in switch line cards?
Accelerated CEF (aCEF)
Value - Mask - and Result (VMR)
On
Switch(config-if)#switchport mode access

20. Enables error-disable for when the port link state is flapping between the up and down states
Switch(config)#errdisable detect cause link-flap
XENPAK - X2 - or SFP+
A name assigned to a ranges of interfaces
Half duplex

21. What is the default age-out time for stale entries in the CAM table?
Store-and-forward
Cabling specification for 10 Mbps Ethernet over Unshielded Twisted Pair (UTP) cabling
300 seconds
Content-Addressable Memory

22. What is the operational mode of a switch port that carries traffic for multiple VLANs?
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#show interfaces status
Trunk
The adjacency table

23. What is the state of packets that are sent to the CEF Layer 3 engine because of missing Layer 2 next-hop addresses?
CEF glean
Routing table and ARP table
Switch(config)#errdisable detect cause gbic-invalid
Source MAC (/48); Destination MAC (/48); Ethertype (/16)

24. Disables CEF operation globally
Switch(config)#mac address-table aging-time {seconds}
Switch(config)#no ip cef
Fast Ethernet over 4 pairs EIA/TIA Category 3 - 4 - 5 UTP
FIB with adjacency table

25. What CEF optimisation replicates the entire FIB table among switch line cards?
Distributed CEF (dCEF)
10GBASE-SR/SW - 10GBASE-LR/LW - 10GBASE-ER/EW - 10GBASE-LX4/LW4 - 10GBASE-CX4
100 metres
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)

26. Selects a switch port interface and enters interface configuration mode
Switch#show interfaces {interface} switchport
Source MAC (/48); Destination MAC (/48); Ethertype (/16)
Wide-Wavelength Division Multiplexing
Switch(config)#interface {type}{module}/{number}

27. Enables error-disable for errors related to 802.1x security
Switch(config)#errdisable detect cause security-violation
Slow response times - low throughput - runts and other input errors on the switch ports
By electrical signalling so that either end of a link can determine what speed the other end is trying to use
Gigabit Ethernet over 1 pair 50 or 62.5 micron MMF or 9 micron SMF (1300 nm laser)

28. What is the name of physical network segment where data packets can collide with one another when being sent?
Collision domain
Fast Ethernet over 62.5/125 micron multimode fibre (MMF) or 9 micron singlemode fibre (SMF)
Switch(config)#errdisable detect cause vmps
Half duplex

29. What is the standard for Gigabit Ethernet (1000 Mbps)?
IEEE 802.3z
Switch#show adjacency [{interface}] [summary | detail]
Value - Mask - and Result (VMR)
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

30. What is the administrative mode of a switch port that carries traffic for multiple VLANs?
Layer 2 source and destination MAC addresses; Layer 3 Time-To-Live (TTL) value and header checksum
Switch#show errdisable recovery
Switch#show running-config interface {interface}
Trunk or dynamic

31. What is the content of TCAM Result entries?
FIB with adjacency table
Tunnel
Numeric values that represent what action to take after the TCAM lookup occurs
Fast Ethernet over 62.5/125 micron multimode fibre (MMF) or 9 micron singlemode fibre (SMF)

32. What are the symptoms of a duplex setting mismatch between two ends of a link?
The table of learned MAC addresses - ports - and VLAN information
Slow response times - low throughput - runts and other input errors on the switch ports
Switch#show cef not-cef-switched
Forwarding Information Base

33. What is 100BASE-TX?
10 km
UTP Fast Ethernet and Gigabit Ethernet
Fast Ethernet over 2 pairs EIA/TIA Category 5 UTP
40 km

34. What CEF adjacency is used to discard packets because of access list or other policy action?
Switch#show interfaces status
Adjacent MAC address (6 octets); Layer 3 engine MAC address (6 octets); EtherType (2 octets)
The Discard adjacency
Switch#show ip cef

35. What is MLS?
Multilayer Switching
Switched virtual interface (SVI)
Carrier Sense Multiple Access Collision Detection
Numeric values that represent what action to take after the TCAM lookup occurs

36. When should CEF be disabled?
1 -2 on one end with 3 -6 on the other end
Switch(config)#errdisable detect cause arp-inspection
Only temporarily for debugging purposes
Content-Addressable Memory

37. What connectors can be used with SFP modules?
40 km
LC - MT-RJ or RJ-45
Switch(config)#errdisable detect cause security-violation
Gigabit Ethernet over 1 pair 8 or 9 micron SMF (1550 nm laser)

38. What is the TCAM Value and Mask for an extended IP access list using TCP/UDP?
Switch(config)#errdisable detect cause l2ptguard
Switch(config)#errdisable recovery interval {seconds}
Source IP (/32) - Destination IP (/32) - Protocol (/16) - IP ToS (/8) - Source port (/16) - Source operator (/4) - Destination port (/16) - Destination operator (/4)
Switch(config-if)#no ip route-cache cef

39. What is 1000BASE-SX?
10 Gigabit Ethernet over 50 or 62.5 micron MMF or 9 micron SMF (1300 nm WWDM laser)
Switch#show interfaces status err-disabled
Gigabit Ethernet over 1 pair 50 or 62.5 micron MMF (850 nm laser)
Switch(config)#errdisable detect cause security-violation

40. What is the name of the switching technology where good frames are received - stored for inspection and then forwarded?
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
With a mask value in addition to binary values to decide which keys in a table are relevant
A three-fold combination of 0 - 1 and X (don't care)
Store-and-forward

41. What is the maximum cabling distance for 10GBASE-LX4/LW4?
Switch(config)#errdisable detect cause l2ptguard
Interconnecting with existing Synchronous Optical Network (SONET) or Synchronous Digital Hierarchy (SDH) networks
IEEE 802.3ab
300 metres for 50 or 62.5 micron MMF; 10 km for 9 micron SMF

42. What tables are maintained by the CEF Layer 3 forwarding engine?
Switch(config)#interface vlan {vlan-id}
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
FIB with adjacency table
The table of learned MAC addresses - ports - and VLAN information

43. How is link duplex mode determined on Fast Ethernet links configured to autonegotiate?
Through exchange of information - which means that for one end to successfully negotiate duplex mode the other end must also be set to autonegotiate
Switch(config)#errdisable detect cause pagp-flap
Switch#show mac address-table count [address {mac-address}] [interface {interface}] [vlan {vlan}]
Cisco Express Forwarding

44. What is 1000BASE-X?
Full duplex if only one of the two stacking connectors is used; Half duplex over a shared bus if if both connectors are used
Switch(config)#interface {type}{module}/{number}
The switch port falls back to default setting of half duplex
Cabling specifications for Gigabit Ethernet

45. Displays switch port information for a specified interface
LAN PHY and WAN PHY
Switch#show interfaces {interface} switchport
Numeric values that represent what action to take after the TCAM lookup occurs
Switch(config)#errdisable detect cause unicast-flood

46. What is the name of a Layer 3 physical interface on a switch?
Feature Manager (FM) and Switching Database Manager (SDM)
Native routed interface
Dynamic
Trunk or dynamic

47. What are the reasons for packets being punted by CEF?
Mask bits set to 1 for Value bits of interest and 0 for Value bits that don't matter
LAN PHY and WAN PHY
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
Manually by administratively disabling and re-enabling the port

48. What is IEEE?
10 Gigabit Ethernet over 9 micron SMF (1310 nm serial laser)
Institute of Electrical and Electronics Engineers
Content-Addressable Memory
300 seconds

49. What is the maximum cabling distance for 10GBASE-CX4?
Content-Addressable Memory
American National Standards Institute
When there are more access list entries and Layer 4 operations than available Mask/Value and LOU entries
15 metres

50. What is FIB?
Tunnel
Down - static access - trunk or tunnel
SVI
Forwarding Information Base