Frequently asked questions
HP Intelligent Resilient
Fabric (IRF)
General
Q. What is HP Intelligent Resilient Fabric, or IRF?
A. HP Intelligent Resilient Fabric (IRF) is the HP innovative Ethernet fabric solution for enterprise data centers. HP IRF
delivers enterprise resiliency that enables customers to build agile networks that are simpler to manage, ready for cloud
deployments, and Software-defined Networking.
Q. How is IRF set up?
A: HP IRF is created by grouping a series of two or more switches together, in one domain, or fabric. The IRF grouped
switches are called a fabric, or domain, and form one single logical switch.
Figure 1. IRF physical and logical views
5900
5900
Logical IRF view
5900
5900
IRF fabric physical switches
Q: Does IRF carry extra costs, or require a license?
A: HP IRF is an integral part of HP Comware network operating system. As is the case with all Comware features, IRF does
not require a special license and is available to use from day one.
Q: How are the IRF switches grouped together?
A: Switches are linked together using any standard 10GbE, 40GbE, or 100G ports to form an HP IRF domain. No special
ports, or dedicated ports are needed to create one IRF domain.
Q: How are the switches in the IRF domain managed?
A: All switches in an IRF domain are represented as a single virtual switch that can be managed using a single Internet
Protocol (IP) address (with one single configuration file). In other words, a network administrator has to manage one
virtual switch.
Q: How many switches can be grouped together using IRF?
A: One HP IRF domain can contain up to nine access layer switches, or up to four core layer switches.
Q: Can I use third-party switches as part of HP IRF configuration?
A: IRF is an HP innovative technology that works only with HP switches built around HP Comware operating system.
Note: Third- party switches, routers, and servers can be attached to the IRF domain.
Q: Can I use switches with differing Comware versions in the same IRF domain?
A: HP IRF requires that all switches in one domain contain the same firmware. As a result, one must avoid using switches
with differing operating system version in the same IRF domain, or fabric.
Q: Does HP IRF use the Spanning Tree Protocol (STP)?
A: HP IRF is a STP-free technology that overcomes the constraints of STP while enhancing networking resilience.
Frequently asked questions | HP Intelligent Resilient Fabric (IRF)
HP IRF benefits
Q: How does IRF simplify networking management?
A: As noted earlier, all switches members of an IRF domain are represented as one virtual switch that can be managed
using a single IP address. For example, in a four member IRF domain, networking management is simplified by up to
75 percent over STP-based configurations.
Q: How does HP IRF improve available networking bandwidth?
A: HP IRF replaces STP, opens blocked paths and adds link aggregation to links between member switches and servers
(downlinks) as well as links to core switches (uplinks). With STP replaced and the addition of link aggregation, the
bandwidth available to an IRF member switch becomes the aggregate bandwidth available to all member switches.
That dramatically enhances the available bandwidth.
Note: FlexFabric 5900CP Switch Series is a next generation data center switches, designed to support converged
networking and storage environments, and supports IRF as well.
Q: Does HP IRF enhance network resiliency?
A: Yes. HP IRF greatly enhances network resiliency as evident in the super-fast <50 msec reconvergence time. The low
latency and quick reconvergence are due to the distributed intelligence built into IRF:
•The topology (MAC, ARP, FIB, ACLs) is entirely distributed across the IRF domain. So, in case of the failure of one switch
within the domain, other switches continue to forward the traffic without any interruption.
•The details of the IRF configuration are distributed to every switch in the IRF domain. That enables switches to return to
normal operations very quickly following any configuration changes.
Q: Can I continue use the advanced features of Comware switches when delaying HP IRF?
A: Using IRF in your network enhances the network capabilities and allows you to continue to use advanced Comware
features such as TRILL, PBB/SPB, advanced L3 (IPv4/IPv6) routing, or even MPLS/VPLS.
HP IRF topologies
Q: What are the best ways to configure switches in IRF domains?
A: There are three ways to configure IRF domains. Two of the physical configurations, or topologies, provide horizontal
scaling, while a new enhanced IRF topology provides vertical scaling. In horizontal topologies, all switches of the IRF
domain reside in the same network layer, such as access layer. Below is a brief description of the IRF topologies.
•IRF Bus fabric: Members of the IRF domain are part of the same network layer, such as access, or core layers. IRF Bus
fabric has one primary member (master) device that manages one or more slave devices. Slave devices act as backup
for the primary device. This topology is a simple one and may be split in the event of failure.
•IRF Ring fabric: More resilient than the bus topology. Failures do not affect the functions of the fabric.
Figure 2. IRF Bus and Ring fabrics
Primary
Slave
Slave
Bus fabric
Primary
Slave
Slave
Slave
Ring fabric
2
Frequently asked questions | HP Intelligent Resilient Fabric (IRF)
•IRF Spine/Leaf fabric: The Spine/Leaf topology is a new enhancement to IRF. It allows customers to create IRF domains
using switches that may reside in two different networking layers, such as core and access layers. More importantly,
Spine/Leaf IRF domains designate devices as either Controlling Bridges (CB), or Port Extenders (PE) devices. Spine
devices are referred to as CBs, while leaf devices are called PEs.
Q: How does the Spine/Leaf IRF topology differ from Bus and Ring domains?
A: The Spine/Leaf IRF fabric can utilize switches in different networking layers. Also, the participating switches may be of
different HP data center switch models.
Q: What are the elements that make up a Spine/Leaf IRF domain?
A: The Spine/Leaf IRF domain consists of two elements; the spine, or the Controlling Bridge (CB) and the leaf, or the
Port Extender (PE).
Q: Which HP switches may be used as control bridges in a Spine/Leaf IRF domain?
A: Various switch within the HP Networking portfolio can be used in different combinations. Please consult your local
HPN sales specialist for more information.
Q: How many switches are supported in one Spine/Leaf IRF domain?
A: The first release of the Spine/Leaf IRF fabric will support up to two CBs per domain. Each CB will support up to
thirty (30) PEs in the first release.
Q: Are there plans to further enhance the Spine/Leaf IRF vertical scaling capabilities?
A: Yes, the scaling capabilities of IRF in a Spine/Leaf configuration will be enhanced by increasing the number of CB per
domain and the number of supported PEs per CB.
Figure 3. IRF Spine/Leaf fabric
CB: 5900
PE: 5900,
5700
PE: 5900,
5700
Servers
Servers
Servers
Servers
Learn more at
hp.com/networking
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Frequently asked questions | HP Intelligent Resilient Fabric (IRF)
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4AA5-3379ENW, April 2015, Rev. 1