Question 1.
In a bridged, IEEE 802.5/Token Ring environment, which combination of bits indicates to the source that a packet has been forwarded across a bridging device?

a) A is 0, C is 0, and there is a RIF.
b) A is 1, C is 0, and RII is 0.
c) A is 0, C is 1, and there is no RIF.
d) A is 1, C is 1, and RII is 1.
e) The question is not applicable in a Token Ring environment.

Answer

Question 2.
Which of the following MAC addresses indicate a RIF is present? Choose all that apply.

a) 08 00 09 D1 95 96
b) 88 00 09 D1 95 96
c) 40 12 A1 23 F1 AB
d) C0 12 A1 23 F1 AB
e) 91 00 12 34 A1 34

Answer

Question 3.
Which types of explorer does the following RIF indicate?

RIF: C8 20 00 11 1f 41 00 20

a) All routes explorer
b) Spanning explorer
c) Specific route
d) Single route explorer

Answer

Answers

Question 1.
In a bridged, IEEE 802.5/Token Ring environment, which combination of bits indicates to the source that a packet has been forwarded across a bridging device?

a) A is 0, C is 0, and there is a RIF.
b) A is 1, C is 0, and RII is 0.
c) A is 0, C is 1, and there is no RIF.
d) A is 1, C is 1, and RII is 1.
e) The question is not applicable in a Token Ring environment.

Answer
d) A is 1, C is 1, and RII is 1.

Explanation
The A (Address Recognized) and C (Frame Copied) bits are contained within the frame status byte in a Token Ring frame. When a frame is copied by a source route bridge to be put out onto another ring, the bridge sets these bits, much as if it were actually the destination station. Additionally, the Routing Information Indicator (RII) in the source address field is set to 1 by the source device.
[2643]

CCIE Topic(s): C,I
CCIE Objective(s): C2,I2
CCNA Topic(s):
CCNA Objective(s):

Question 2.
Which of the following MAC addresses indicate a RIF is present? Choose all that apply.

a) 08 00 09 D1 95 96
b) 88 00 09 D1 95 96
c) 40 12 A1 23 F1 AB
d) C0 12 A1 23 F1 AB
e) 91 00 12 34 A1 34

Answer
b) 88 00 09 D1 95 96
d) C0 12 A1 23 F1 AB
e) 91 00 12 34 A1 34

Explanation
In each of the correct choices the first bit, or RII, is set to a 1 to indicate a RIF is present. In each of the other choices, the first bit is NOT set to a 1. See below.

08 = 0000 1000 in binary
88 = 1000 1000 in binary
40 = 0100 0000 in binary
C0 = 1100 0000 in binary
91 = 1001 0001 in binary

CCIE Topic(s): C,I
CCIE Objective(s): C2,I2
CCNA Topic(s):
CCNA Objective(s):

Question 3.
Which types of explorer does the following RIF indicate?

RIF: C8 20 00 11 1f 41 00 20

a) All routes explorer
b) Spanning explorer
c) Specific route
d) Single route explorer

Answer
b) Spanning explorer
d) Single route explorer

Explanation
A single route explorer is a spanning explorer. The RC decodes as follows:

The table above shows the following:

Bits 15-13 show that the packet is a 110 spanning route explorer.

Bits 12-8 show that the RIF is 01000 or 8 bytes in size.

Bit 7 shows that the direction is 0 or read from left to right.

Bits 6-4 show that the largest frame is 010 or 2052 bytes.

Remember also that the final 4 bits are reserved and always 0.
[2645]

CCIE Topic(s): C,I
CCIE Objective(s): C2,I2
CCNA Topic(s):
CCNA Objective(s):