More detail please visit this datasheet: S5500-24GF4XF-E

Intelligent Resilient Framework 2 (IRF2)

IRF2 provides the following benefits:

High scalability: Plug-n-play device aggregation can be achieved by add

ing one or more switches into the IRF2 stack and enabling IRF2 stacking

on the new device. New devices can be managed with a single IP, and

upgraded at the same time to reduce network expansion cost.

High reliability: The IRF2 1:N backup technology allows each sub device

in the IRF2 stack to serve as the backup of the main device, creating

control and data link redundancy.

Availability: DH-S5500-24GF4XF-E implements IRF2 through standard

Gigabit Ethernet (1GE) ports or Ten Gigabit Ethernet (10GE) ports which

allocates bandwidth for business and application access and reasonably

splits local traffic and upstream traffic. IRF2 rules not only able to be

obeyed within and across the rack, but also across the LAN.

Abundant QoS

DH-S5500-24GF4XF-E supports packet filtering at layer 2 through layer

4, and traffic classification based on source MAC addresses, destination

MAC addresses, source IP addresses, destination IP addresses, TCP/UDP

port numbers, protocol types, and VLANs. It supports flexible queue

scheduling algorithms based on ports and queues, including strict prior

ity (SP), weighted round Robin (WRR) and SP+WRR. The DH-S5500-XF-E

switch series enables committed access rate (CAR) with the minimum

granularity of 8 kbps. It supports port mirroring in the outbound and

inbound directions, to monitor the packets on the specific ports, and

to mirror the packets to the monitor port for network detection and

troubleshooting.