Manual:CRS3xx series switches

Applies to RouterOS: v6.41 +

Summary

The Cloud Router Switch series are highly integrated switches with high performance ARM CPU and feature-rich packet processor. The CRS switches can be designed into various Ethernet applications including unmanaged switch, Layer 2 managed switch, carrier switch and wired unified packet processing.

Warning: This article applies to CRS3xx series switches and not to CRS1xx/CRS2xx series switches.

Features

Features	Description
Forwarding	Configurable ports for switching or routing Full non-blocking wirespeed switching Up to 16k MAC entries in Unicast FDB for Layer 2 unicast forwarding Up to 1k MAC entries in Multicast FDB for multicast forwarding Up to 256 MAC entries in Reserved FDB for control and management purposes All Forwarding Databases support IVL and SVL Configurable Port based MAC learning limit Jumbo frame support
Mirroring	Various types of mirroring: Port based mirroring VLAN based mirroring MAC based mirroring 2 independent mirroring analyzer ports
VLAN	Fully compatible with IEEE802.1Q and IEEE802.1ad VLAN 4k active VLANs Flexible VLAN assignment: Port based VLAN VLAN filtering

Models

This table clarifies main differences between Cloud Router Switch models.

Model	Switch Chip	CPU	Wireless	SFP+ port	Access Control List	Jumbo Frame (Bytes)
CRS326-24G-2S+	Marvell-98DX3236	800MHz	-	+	+	10218
CRS317-1G-16S+	Marvell-98DX8216	800MHz	-	+	+	10218

Abbreviations

• FDB - Forwarding Database
• MDB - Multicast Database

Port Switching

Since v6.40rc29 bridges will handle all Layer2 forwarding and the use of switch chip (hw-offload) will automatically turn on if appropriate conditions are met. The rest of RouterOS Switch features remain untouched in usual menus. By default all newly created bridge ports have hw=yes option and it allows enabling of hw-offload when possible. If such functionality is not required, it can be disabled by hw=no on bridge port to have completely software operated bridging.

Note: Downgrading to previous RouterOS versions will not restore master-port configuration. The bridge with no hw-offload will appear instead and master-port configuration will have to be redone from the beginning.

Example

/interface bridge 
add name=bridge1 igmp-snooping=no  protocol-mode=none
/interface bridge port
add bridge=bridge1 interface=ether2
add bridge=bridge1 interface=ether3
add bridge=bridge1 interface=ether4
add bridge=bridge1 interface=ether5

[admin@MikroTik] > interface bridge port print 
Flags: X - disabled, I - inactive, D - dynamic, H - hw-offload 
 #     INTERFACE              BRIDGE              HW  PVID PRIORITY  PATH-COST INTERNAL-PATH-COST    HORIZON
 0   H ether2                 bridge1             yes    1     0x80         10                 10       none
 1   H ether3                 bridge1             yes    1     0x80         10                 10       none
 2   H ether4                 bridge1             yes    1     0x80         10                 10       none
 3   H ether5                 bridge1             yes    1     0x80         10                 10       none

Note: On CRS3xx series switches bridge STP/RSTP/MSTP, IGMP Snooping and VLAN filtering settings don't affect hardware offloading, bonding on the other hand disables hardware offloading

Host Table

Sub-menu: /interface bridge host

Property	Description
age (read-only: time)	The time since the last packet was received from the host
bridge (read-only: name)	The bridge the entry belongs to
external-fdb (read-only: flag)	Whether the host was learned using wireless registration table
local (read-only: flag)	Whether the host entry is of the bridge itself (that way all local interfaces are shown)
mac-address (read-only: MAC address)	Host's MAC address
on-interface (read-only: name)	Which of the bridged interfaces the host is connected to

Example

To get the active host table:

[admin@MikroTik] /interface bridge host> print 
Flags: L - local, E - external-fdb 
  BRIDGE           MAC-ADDRESS       ON-INTERFACE          AGE                 
  bridge1          00:00:00:00:00:01 ether2                3s                  
  bridge1          00:01:29:FF:1D:CC ether2                0s                  
L bridge1          00:0C:42:52:2E:CF ether2                0s                  
  bridge1          00:0C:42:52:2E:D0 ether2                3s                  
  bridge1          00:0C:42:5C:A5:AE ether2                0s                  
[admin@MikroTik] /interface bridge host>

VLAN

TODO

STP/RSTP/MSTP

TODO

IGMP Snooping

IGMP Snooping which controls multicast streams and prevents multicast flooding is implemented in RouterOS starting from version 6.41.
It's settings are placed in bridge menu and it works independently in every bridge interface.
Software driven implementation works on all devices with RouterOS but CRS1xx/2xx/3xx series switches also support IGMP Snooping with hardware offloading.

Sub-menu: /interface bridge /interface bridge mdb

• Enabling IGMP Snooping on Bridge.

/interface bridge set bridge1 igmp-snooping=yes

• Monitoring multicast groups in the Bridge Multicast Database

[admin@MikroTik] > interface bridge mdb print 
BRIDGE                   VID GROUP                                              PORTS           
bridge1                  200 229.1.1.2                                          ether3          
                                                                                ether2          
                                                                                ether1          
bridge1                  300 231.1.3.3                                          ether4          
                                                                                ether3          
                                                                                ether2          
bridge1                  400 229.10.10.4                                        ether4          
                                                                                ether3          
bridge1                  500 234.5.1.5                                          ether5          
                                                                                ether1          
[admin@MikroTik] > 

Global Switch Settings

TODO

Port Settings

TODO

Switch Rules (ACL)=

TODO

See also

• CRS examples
• CRS features
• Switch Chip Features
• MTU on RouterBOARD

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