Issue
What benefits does IRF provide to the network?
Environment
What is IRF?
Cause
IRF overview and benefits described.
Resolution
Basic IRF Concepts:
The devices that form an IRF virtual device are called IRF member devices. A member device assumes the role of master or slave. An IRF stack contains only one master, which manages the IRF virtual device. All other members operate as slaves and as backups for the master. When the master fails, the IRF virtual device automatically elects a new master from one of the slaves. Master and slaves are selected through the role election mechanism.
A logical IRF port is a logical port dedicated to the internal connection of an IRF virtual device. These ports cannot act as access, trunk or hybrid ports. An IRF port is effective only when it is bound to a physical IRF port.
Physical ports used for connecting members of an IRF virtual device are called
physical IRF ports. Typically, an Ethernet port or optical port forwards frames to the network. When a physical port is bound to an IRF port, it acts as a physical IRF port and forwards data traffic such as IRF-related negotiation frames and data traffic among members.
An IRF stack can have a daisy chain topology or a ring topology. A ring connection is more reliable than the daisy chain connection. In a daisy chain topology, the failure of one link can cause the IRF virtual device to partition into two independent IRF virtual devices, which can disrupt connectivity as well as IRF functioning. The failure of a link in a ring connection results in a daisy chain connection, and does not affect IRF services.
IRF application scenario: Increasing port density
IRF provides a simple, cost-effective solution to the issues that arise when use
population exceeds the available network ports. With IRF deployed, one can add
new members to the virtual IRF device, adding port density with minimal
configuration of the new switches.
IRF application scenario: Expanding system processing capabilities
When the forwarding capability of the core switch cannot satisfy users’ needs, one can add a switch to form an IRF stacking system with the original core switch. If the forwarding capability of one switch is 64 Mbps, the forwarding capability of the whole stack system is 128 Mbps after another switch is added. Note that this increases the forwarding capability of the entire stacking system, not a single switch.
IRF application scenario: Expanding bandwidth
One can increase the uplink bandwidth of an edge switch by adding another switch
to form a stacking system with the existing edge switch and can configure multiple physical links of the member devices as an aggregation group to increase the bandwidth of the link to the core switch.
IRF simplifies networks
For example, the user can combine multiple distribution layer switches into one IRF stack. All of the switches have the same routing table and can route packets received from the edge switches. The IRF master will run the routing protocol for the entire virtual device.
When configured as an IRF stack, the distribution layer switches now act as a single virtual switch. Loops can still occur, however between an edge switch and the IRF virtual switch. In order to retain the redundant links between the edge and distribution layers, the redundant links can be combined in a link aggregation, creating a single logical link that spans two physical devices in the IRF virtual switch.
Advantages of this topology The IRF topology is simpler to configure and maintain
than a MSTP/VRRP solution. In the IRF implementation, the virtual switch is
configured as if it were a single device. If the same switches were running MSTP and VRRP, each switch would need a distinctly different configuration to ensure the correct election of MSTP Root Bridge and VRRP Master. Furthermore, each switch would need to be configured separately for all routing and switching functions.
The devices that form an IRF virtual device are called IRF member devices. A member device assumes the role of master or slave. An IRF stack contains only one master, which manages the IRF virtual device. All other members operate as slaves and as backups for the master. When the master fails, the IRF virtual device automatically elects a new master from one of the slaves. Master and slaves are selected through the role election mechanism.
A logical IRF port is a logical port dedicated to the internal connection of an IRF virtual device. These ports cannot act as access, trunk or hybrid ports. An IRF port is effective only when it is bound to a physical IRF port.
Physical ports used for connecting members of an IRF virtual device are called
physical IRF ports. Typically, an Ethernet port or optical port forwards frames to the network. When a physical port is bound to an IRF port, it acts as a physical IRF port and forwards data traffic such as IRF-related negotiation frames and data traffic among members.
An IRF stack can have a daisy chain topology or a ring topology. A ring connection is more reliable than the daisy chain connection. In a daisy chain topology, the failure of one link can cause the IRF virtual device to partition into two independent IRF virtual devices, which can disrupt connectivity as well as IRF functioning. The failure of a link in a ring connection results in a daisy chain connection, and does not affect IRF services.
IRF application scenario: Increasing port density
IRF provides a simple, cost-effective solution to the issues that arise when use
population exceeds the available network ports. With IRF deployed, one can add
new members to the virtual IRF device, adding port density with minimal
configuration of the new switches.
IRF application scenario: Expanding system processing capabilities
When the forwarding capability of the core switch cannot satisfy users’ needs, one can add a switch to form an IRF stacking system with the original core switch. If the forwarding capability of one switch is 64 Mbps, the forwarding capability of the whole stack system is 128 Mbps after another switch is added. Note that this increases the forwarding capability of the entire stacking system, not a single switch.
IRF application scenario: Expanding bandwidth
One can increase the uplink bandwidth of an edge switch by adding another switch
to form a stacking system with the existing edge switch and can configure multiple physical links of the member devices as an aggregation group to increase the bandwidth of the link to the core switch.
IRF simplifies networks
For example, the user can combine multiple distribution layer switches into one IRF stack. All of the switches have the same routing table and can route packets received from the edge switches. The IRF master will run the routing protocol for the entire virtual device.
When configured as an IRF stack, the distribution layer switches now act as a single virtual switch. Loops can still occur, however between an edge switch and the IRF virtual switch. In order to retain the redundant links between the edge and distribution layers, the redundant links can be combined in a link aggregation, creating a single logical link that spans two physical devices in the IRF virtual switch.
Advantages of this topology The IRF topology is simpler to configure and maintain
than a MSTP/VRRP solution. In the IRF implementation, the virtual switch is
configured as if it were a single device. If the same switches were running MSTP and VRRP, each switch would need a distinctly different configuration to ensure the correct election of MSTP Root Bridge and VRRP Master. Furthermore, each switch would need to be configured separately for all routing and switching functions.
Hewlett Packard Enterprise believes in being unconditionally inclusive. Efforts to replace noninclusive terms in our active products are ongoing.