Cisco UCS End Host Mode and Static PIN Grouping for SAN Design

300-610 By islever Editorial Last updated

Evaluate options for Ethernet connectivity Evaluate UCS-X design options based on deployment and performance requirements

Short answer

BC End Host Mode prevents domain ID exhaustion and Static PIN Grouping maps traffic to specific fabric interconnect ports.

Question

A network engineer is using a Cisco UCS environment connected to a Fibre Channel storage array. The Cisco UCS environment must be connected to an existing SAN network, and several Cisco MDS 9000 Series Switches must be added to increase storage density. The solution must not exhaust the SAN network from the list of available domain IDs after connecting. Also, most of the SAN traffic must be mapped from the Cisco UCS blades to a specific group of the fabric interconnect ports. Which two features must be deployed to meet these requirements? (Choose two.)
  1. dynamic port pinning
  2. end host mode Correct Answer
  3. static PIN grouping Correct Answer
  4. N-Port ID virtualization
  5. priority flow control

Key Takeaways

The question tests knowledge of UCS operating modes that impact FC fabric resources (domain IDs) and traffic steering mechanisms.

Learn how Cisco UCS End Host Mode conserves Fibre Channel domain IDs and Static PIN Grouping maps blade traffic to specific fabric interconnect ports in SAN design.

Common mistake: Choosing N-Port ID Virtualization (NPIV) is a common trap because it relates to FC efficiency, but it does not solve domain ID exhaustion at the switch level or provide static port mapping.

Expert Analysis

Conserving Domain IDs with End Host Mode

The scenario requires connecting Cisco UCS to an existing SAN without exhausting the limited pool of Fibre Channel domain IDs. In standard FC switching, each switch port can request a domain ID. However, when End Host Mode (EHM) is enabled on the Cisco UCS Fabric Interconnects, they act as end-host devices rather than switches. This means they do not participate in the fabric’s spanning tree protocol or request domain IDs for their uplink ports. Instead, the blade servers’ HBAs register directly with the upstream MDS switches, which drastically reduces the number of domain IDs consumed by the UCS infrastructure itself. This directly satisfies the constraint to prevent domain ID exhaustion.

Traffic Mapping via Static PIN Grouping

The second requirement is to map most SAN traffic from specific blades to a specific group of fabric interconnect ports. While dynamic mechanisms exist, Static PIN Grouping allows the administrator to explicitly define which HBA ports on the blades are pinned to which specific Fabric Interconnect ports (or uplinks). This ensures deterministic traffic flow and load balancing across the designated physical paths, satisfying the need to map traffic to a specific group of ports. Dynamic pinning would change based on link status, whereas static grouping provides the fixed mapping described.

Why Other Options Fail

N-Port ID Virtualization (NPIV) allows multiple virtual WWNs per physical port but does not address domain ID consumption by the switch layer or explicit port-to-port mapping. Priority Flow Control (PFC) handles lossless Ethernet/QoS but is irrelevant to FC domain IDs or port mapping. Therefore, EHM and Static PIN Grouping are the required features.

Exam Strategy

When seeing 'domain ID exhaustion' in a Cisco UCS/FC question, immediately look for End Host Mode. When seeing 'map traffic to specific ports' or 'deterministic path', consider Static Pinning over Dynamic Pinning. Always check if the requirement involves switch behavior (EHM) vs. host behavior (NPIV).

Frequently Asked Questions

How does End Host Mode save domain IDs?

In End Host Mode, the Fabric Interconnects do not request domain IDs from the upstream MDS switches. The blade HBAs communicate directly with the MDS, treating the UCS as a passive host rather than an active switch.

What is the difference between Static and Dynamic PIN Grouping?

Static PIN Grouping forces traffic from specific HBA ports to specific Fabric Interconnect uplinks regardless of link state changes. Dynamic Pinning automatically adjusts pinning based on active links, which may not satisfy strict mapping requirements.

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Community Votes

B
75%
C
25%

75% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 10 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 10

  1. yazmeh 👍 4
    The correct answers are: B. End Host Mode: End Host Mode is essential because it allows the Cisco UCS fabric interconnects to behave as end-host devices, conserving domain IDs and facilitating the control of traffic flow from UCS blades to the SAN. This ensures efficient utilization of domain IDs and simplifies management. D. N-Port ID Virtualization (NPIV): NPIV is crucial for allowing multiple N-Port WWNs to share a single physical port on the Fibre Channel switch. It enables each UCS blade to have its unique WWN and independently log in to the SAN fabric without the need for a separate physical port for each blade. This addresses the requirement to map SAN traffic from UCS blades to specific fabric interconnect ports while conserving domain IDs. These two options (B and D) are the correct answers because they directly align with the requirements mentioned in the question, ensuring efficient use of SAN resources and control over UCS blade traffic. [High quality and reasonable used Cisco = https://altatechnologies.com/collections/used-cisco ]
  2. Fcpoultry 👍 3 Answered B
    B. end host mode ("The solution must not exhaust the SAN network from the list of available domain IDs after connecting. C. static PIN grouping ("most of the SAN traffic must be mapped from the Cisco UCS blades to a specific group of the fabric interconnect ports" So, "B"& "C" are the correct answers.
  3. husam_shabeeb 👍 3
    A& E SORRY
  4. husam_shabeeb 👍 1
    A network engineer is using a Cisco UCS environment connected to a Fibre Channel storage array. 09/12/2022 – by Mod_GuideK0 A network engineer is using a Cisco UCS environment connected to a Fibre Channel storage array. The Cisco UCS environment must be connected to an existing SAN network, and several Cisco MDS 9000 Series Switches must be added to increase storage density. The solution must not exhaust the SAN network from the list of available domain IDs after connecting Also, most of the SAN traffic must be mapped from the Cisco UCS blades to a specific group of the fabric interconnect ports Which two features must be deployed to meet these requirements? (Choose two.) A. end host mode B. static PIN grouping C. priority flow control D. N-Port lD virtualization E. dynamic port pinning HIDE ANSWERSCorrect Answer: AD Explanation/Reference: Explanation:
  5. StonedGhost254 👍 1 Answered B
    As it requires two answers, I chose B&C The correct features to deploy are End Host Mode (or FC End Host Mode) and Static PIN Grouping. End Host Mode: Configures the fabric interconnect to act as an end-host rather than a traditional switch, preventing it from participating in the SAN's Spanning Tree Protocol (STP) or requesting a domain ID, which conserves valuable domain IDs. Static PIN Grouping: Allows you to explicitly map SAN traffic from specific Cisco UCS vHBAs to particular upstream fabric interconnect ports, satisfying the traffic-pinning requirement.
Show 5 more comments
  1. lurker8000 👍 1
    I think I'm gonna go with B and C also. Pinning is required for the requirement >>> "most of the SAN traffic must be mapped from the Cisco UCS blades to a specific group of the fabric interconnect ports" End host mode should handle Domain ID exhaustion.
  2. Fcpoultry 👍 1
    Actually, the option "D" doesn't align with this requirement: "most of the SAN traffic must be mapped from the Cisco UCS blades to a specific group of the fabric interconnect ports"
  3. f143c37 👍 1
    What does PFC have to do with these requirements? It's A and B
  4. garza_javi 👍 1
    both B and C
  5. husam_shabeeb 👍 1
    CHOSE 2 !!

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