B - because only one next hop in forwarding table C- becuse TTL=1 limiting bgp connection to be established only over loopbacks interface https://www.juniper.net/documentation/us/en/software/junos/bgp/topics/topic-map/multihop-sessions.html Use the multihop statement to alter the default use of the neighbor ' s physical address. In addition, you can also specify a time-to-live (TTL) value in the BGP packets to control how far they propagate. We use a TTL value of 1 to ensure that the session cannot be established across any other backdoor links in the network.

Reviewing MST Configuration:

The configuration shown in the exhibit indicates MST (Multiple Spanning Tree) configuration for DS-1 and DS-2 switches.

For DS-1:

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mstp {

configuration-name Region-1;

revision-level 1;

interface ge-0/0/8;

interface ge-0/0/9;

interface ge-0/0/10;

interface ge-0/0/12;

msti 1 {

bridge-priority 4k;

vlan 10-19;

}

msti 2 {

bridge-priority 8k;

vlan 20-29;

}

}

For DS-2:

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mstp {

configuration-name Region-1;

revision-level 1;

interface ge-0/0/8;

interface ge-0/0/9;

interface ge-0/0/10;

interface ge-0/0/12;

msti 1 {

bridge-priority 8k;

vlan 10-19;

}

}

Understanding Bridge Priority:

In MSTP, the switch with the lowest bridge priority becomes the root bridge for the respective MST instance.

For MSTI 1:

DS-1 bridge-priority is 4k (4096)

DS-2 bridge-priority is 8k (8192)

Thus, DS-1 will be the root bridge for MSTI 1.

For MSTI 2:

DS-1 bridge-priority is 8k (8192)

DS-2 does not participate in MSTI 2.

Thus, DS-1 will be the root bridge for MSTI 2.

Analyzing VLAN Assignments:

DS-1 MSTI 1: VLANs 10-19, priority 4k

DS-1 MSTI 2: VLANs 20-29, priority 8k

DS-2 MSTI 1: VLANs 10-19, priority 8k

DS-2 does not have MSTI 2 configuration.

Conclusion:

DS-1 is the root bridge for MSTI 1 (C)

DS-2 does not participate in MSTI 2 (eliminates A)

DS-1 is the root bridge for MSTI 2 (D)

DS-2 is not the root bridge for MSTI 1 (eliminates B)

References:

Configuration snippets

Understanding of MSTP priorities and root bridge election

Based on the provided configuration, let ' s analyze each term to determine the correct forwarding class and acceptance of traffic:

Term 1 :

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term 1 {

from {

protocol udp;

port [ 16000 16002 ];

}

then {

loss-priority high;

forwarding-class voice;

}

}

This term specifies that UDP traffic on ports 16000 and 16002 is assigned a high loss priority and placed in the " voice " forwarding class. The action does not include an explicit " accept; " statement, but traffic matching this term will be forwarded according to the specified forwarding class and priority.

Term 2 :

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term 2 {

from {

protocol tcp;

port 4423;

}

then {

loss-priority low;

forwarding-class best-effort;

accept;

}

}

This term specifies that TCP traffic on port 4423 is assigned a low loss priority and placed in the " best-effort " forwarding class. It explicitly includes an " accept; " statement, meaning this traffic will be accepted and processed according to these parameters.

Term 3 :

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term 3 {

from {

protocol tcp;

port [ 22 80 443 ];

}

then {

forwarding-class af;

}

}

This term specifies that TCP traffic on ports 22 (default SSH port), 80 (HTTP), and 443 (HTTPS) will be placed in the " af " forwarding class. There is no explicit " accept; " statement here, but the traffic matching this term will be forwarded according to the specified forwarding class.

Term 4 :

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term 4 {

then {

forwarding-class best-effort;

accept;

}

}

This term applies to any traffic that does not match the previous terms. Such traffic will be placed in the " best-effort " forwarding class and explicitly accepted.

Statement A : " SSH traffic using the default port will be placed in the af forwarding class and accepted. "

Correct . Term 3 matches TCP traffic on port 22 (default SSH port) and assigns it to the " af " forwarding class. Although " accept " is not explicitly stated, the traffic is forwarded based on this class.

Statement B : " SSH traffic using the default port will be placed in the best-effort forwarding class and accepted. "

Incorrect . The default SSH port (22) matches Term 3, which places it in the " af " forwarding class, not " best-effort. "

Statement C : " UDP traffic using the 16000 port will be placed in the voice forwarding class and accepted. "

Correct . Term 1 matches UDP traffic on port 16000 and places it in the " voice " forwarding class. Although " accept " is not explicitly stated, the traffic is processed based on the forwarding class and priority.

Statement D : " UDP traffic using the 16000 port will be placed in the best-effort forwarding class and accepted. "

Incorrect . UDP traffic on port 16000 matches Term 1, which places it in the " voice " forwarding class, not " best-effort. "

Juniper Networks Configuration Guidelines and Command References

Detailed command references from the uploaded files, particularly those related to firewall and CoS configurations​​​​​​​​​​​​​​.

Analysis: References: