SwOS/CRS3xx

Summary

SwOS is an operating system designed specifically for administration of MikroTik switch products.

SwOS is configurable from your web browser. It gives you all the basic functionality for a managed switch, plus more: allows to manage port-to-port forwarding, broadcast storm control, apply MAC filter, configure VLANs, mirror traffic, apply bandwidth limitation and even adjust some MAC and IP header fields.

Warning: Each RouterBoard switch series device has its own firmware which cannot be installed on other series models!

CRS326-24G-2S+ supports SwOS v2.0 and newer.
CRS317-1G-16S+ supports SwOS v2.3 and newer.

CRS328-24P-4S+ supports SwOS v2.7 and newer.
CRS328-4C-20S-4S+ supports SwOS v2.7 and newer.
CRS305-1G-4S+ supports SwOS v2.8 and newer.
CRS309-1G-8S+ supports SwOS v2.8 and newer.

CRS3xx series features

Features	Description
Forwarding	Full non-blocking wirespeed switching Up to 16k MAC entries in Host table Forwarding Database works based on SVL or IVL Port Isolation Jumbo frame support - 10218 bytes
Spanning Tree Protocol	RSTP support
Link Aggregation	Supports 802.3ad LACP groups Supports static link aggregation groups Up to 16 link aggregation groups Up to 8 member ports per a group Hardware automatic failover and load balancing
Multicast Forwarding	IGMP Snooping support Unknown Multicast Filtering
Mirroring	Port based mirroring
VLAN	Fully compatible with IEEE802.1Q Port based VLAN Up to 250 VLAN entries (limited by SwOS) VLAN filtering
Security	Port Lock Broadcast Storm Control DHCP & PPPoE Snooping
Quality of Service (QoS)	Ingress traffic limiting
Access Control List	Ingress ACL tables Up to 32 ACL rules (limited by SwOS) Classification based on ports, L2, L3, L4 protocol header fields ACL actions include filtering, forwarding and modifying of the protocol header fields

Models

This table clarifies the main differences between Cloud Router Switch models.

Model	Switch Chip	Serial console	PoE-in support	PoE-out support	Health monitor
CRS326-24G-2S+	Marvell-98DX3236	+	ether1, Passive PoE	-	CPU temperature
CRS328-24P-4S+	Marvell-98DX3236	+	-	ether1 - ether24, 802.3af/at	CPU and board temperature, fan speed, PSU voltage and current
CRS328-4C-20S-4S+	Marvell-98DX3236	+	-	-	CPU temperature, fan speed, PSU state
CRS317-1G-16S+	Marvell-98DX8216	+	-	-	CPU temperature, fan speed, PSU state
CRS305-1G-4S+	Marvell-98DX3236	-	ether1, 802.3af/at	-	CPU temperature
CRS309-1G-8S+	Marvell-98DX8208	+	ether1, 802.3af/at	-	CPU temperature

Connecting to the Switch

Open your web browser and enter IP address of your Switch (192.168.88.1 by default) and login screen will appear.

SwOS default IP address: 192.168.88.1, user name: admin and there is no password.

Note: MikroTik Neighbor Discovery protocol tools can be used to discover IP address of Mikrotik switch. Manual:IP/Neighbor_discovery. Currently LLDP is not supported.

Interface Overview

SwOS interface menu consists of multiple tabs depending on the device model. These are all possible SwOS menus: Link, PoE, SFP, Port Isolation, LAG, Forwarding, RSTP, Stats, Errors, Hist, VLAN, VLANs, Hosts, IGMP, SNMP, ACL, System, Health and Upgrade.

Description of buttons in SwOS configuration tool:

Append - add new item to the end of the list
Apply All - applies current configuration changes
Cut - removes item from the list
Clear - resets properties of the item
Discard Changes - removes unsaved configuration
Insert - add new item to the list (places it before current item)
Sort - sort VLAN table by VLAN-IDs; sort host table by MAC addresses

Change Password - changes password of the switch
Logout - logout from current Switch
Reboot - reboot the switch
Reset Configuration - reset configuration back to factory defaults
Choose File - browse for upgrade or backup file
Upgrade - upgrade firmware of the Switch
Restore Backup - restore Switch using selected backup file
Save Backup - generate and download backup file from the Switch

System

System Tab performs the following functions:

General information about Switch
Switch management
Configuration reset
Backup and restore configuration

Note: SwOS uses a simple algorithm to ensure TCP/IP communication - it just replies to the same IP and MAC address packet came from. This way there is no need for Default Gateway on the device itself.

Property	Description
Address Acquisition	Specify which address acquisition method to use: `DHCP with fallback` - For first 10 seconds switch uses DHCP client. If request is unsuccessful, then address is set as a Static IP Address value `static` - Address is set as a Static IP Address value `DHCP only` - Switch uses DHCP client to acquire address
Static IP Address	IP address of the switch in case of Address Acquisition is set as `DHCP with fallback` or `static`
Identity	Name of the switch (for Mikrotik Neighbor Discovery protocol)
Allow From	IP address from which the switch is accessible. Default value is '0.0.0.0/0' - any address
Allow From Ports	List of switch ports from which it is accessible
Allow From VLAN	VLAN ID from which the switch is accessible (VLAN Mode on ingress port must be other than `disabled` in order to connect)
Watchdog	Enable or disable system Watchdog. It will reset CPU of the switch in case of fault condition
Independent VLAN Lookup	Enable or disable independent VLAN lookup in the Host table for packet forwarding
IGMP Snooping	Enable or disable IGMP Snooping
Mikrotik Discovery Protocol	Enable or disable Mikrotik Neighbor Discovery protocol
MAC Address	MAC address of the switch (Read-only)
Serial Number	Serial number of the switch (Read-only)
Board Name	MikroTik model name of the switch (Read-only)
Uptime	Current switch uptime (Read-only)

DHCP & PPPoE Snooping

Property	Description
Trusted Ports	Group of ports, which allows DHCP or PPPoE servers to provide a requested information. Mainly used to limit unauthorized servers to provide malicious information for users, access ports usually do not configure as trusted
Add Information Option	Enables or disables DHCP Option-82 information. When enabled, the Option-82 information (Agent Remote ID and Circuit ID) is added for DHCP packets received from untrusted ports. Can be used together with Option-82 capable DHCP server to assign IP addresses and implement policies

Password and Backup

Link

Link Tab allows you to configure each interface settings and monitor link status

Property	Description
Enabled	Enable or disable port
Name	Editable port name
Link Status	Current link status (Read-only)
Auto Negotiation	Enable or disable auto negotiation
Speed	Specify speed setting of the port (requires auto negotiation to be disabled)
Full Duplex	Specify duplex mode of the port (requires auto negotiation to be disabled)
Flow control	Enable or disable 802.3x Flow control

PoE

Devices with PoE-out support have some configuration options and certain monitoring features, like PoE-out current, voltage, etc. For more detailed description, see Manual:PoE-Out.

SFP

SFP tab allows you to monitor status of SFP/SFP+ modules.

Port Isolation

Port Isolation table allows or restricts traffic forwarding between specific ports. By default, all available switch chip ports can communicate with any other port, there is no isolation used. When the checkbox is enabled/ticked you allow to forward traffic from this port towards the ticked port. Below are some port isolation examples.

Note: It is possible to check/uncheck multiple checkboxes by checking one of them and then dragging horizontally (Click & Drag).

Note: (R)STP will only work properly in Private VLAN setups. In setups with multiple isolated switch groups (R)STP might not properly receive BPDUs and therefore fail to detect network loops.

LAG

IEEE 802.3ad (LACP) compatible link aggregation is supported, as well as static link aggregation to ensure failover and load balancing based on Layer2 and Layer3 hashing.

Up to 16 link aggregation groups with up to 8 ports per a group are supported.

Each individual port can be configured as Passive LACP, Active LACP or a Static LAG port.

Property	Description
Mode (default: passive)	Specify LACP packet exchange mode or Static LAG mode on ports: `Passive`: Place port in listening state, use LACP only when it's contrary port uses active LACP mode `Active`: Prefer to start LACP regardless contrary port mode `Static`: Set port in a Static LAG mode

Property	Description
Group	Specify a Static LAG group
Trunk (read only)	Represents group number port belongs to.
Partner (read only)	Represents partner mac-address.

Forwarding

Forwarding Tab provides advanced forwarding options among switch ports, port locking, port mirroring, bandwidth limit and broadcast storm control features.

Property	Description
Port Lock	`Port Lock` - Enable or disable MAC address learning on this port `Lock On First` - Enable or disable MAC address learning on this port (MAC address from the first received packet will still be learnt)
Port Mirroring	`Mirror Ingress` - Whether traffic entering this port must be copied and forwarded to mirroring target port `Mirror Egress` - Whether traffic leaving this port must be copied and forwarded to mirroring target port `Mirror To` - Mirroring target port
Broadcast Storm Control	`Storm Rate (%)` - Limit the number of broadcast packets transmitted by an interface. The rate is measured in percents of the link speed. `Include Unknown Unicast` - Include unicast packets without an entry in host table in `Storm Rate` limitation
Bandwidth Limit	`Ingress Rate` - Limit traffic entering this port (bps)

RSTP

Per port and global RSTP configuration and monitoring is available in the RSTP menu.

Property	Description
Bridge Priority (hex)	RSTP bridge priority for Root Bridge selection
Port Cost Mode	There are two methods for automatically detecting RSTP port cost depending on link speed. `short`: 10G - 2; 1G - 4; 100M - 10; 10M - 100 `long`: 10G - 2000; 1G - 20000; 100M - 200000; 10M - 2000000
Root Bridge	The priority and MAC address of the selected Root Bridge in the network (Read-only)

Property	Description
RSTP	Enable or disable STP/RSTP functionality on this port
Mode	Shows STP/RSTP functionality mode on specific port (Read-only): `RSTP` `STP`
Role	Shows specific port role (Read-only): `root` - port that is facing towards the root bridge and will be used to forward traffic from/to the root bridge `alternate` - port that is facing towards root bridge, but is not going to forward traffic (a backup for root port) `backup` - port that is facing away from the root bridge, but is not going to forward traffic (a backup for non-root port) `designated` - port that is facing away from the root bridge and is going to forward traffic `disabled` - port that is not strictly part of STP (RSTP functionality is disabled)
Root Path Cost	Shows root path cost for ports that are facing root bridge (Read-only)
Type	`edge` - ports that are not supposed to receive any BPDUs, should be connected to end station (Read-only) `point-to-point` - ports that operates in full-duplex links, can be part of STP and operate in forwarding state (Read-only)
State	Shows each port state (Read-only): `forwarding` - port participates in traffic forwarding and is learning MAC addresses, is receiving BPDUs `discarding` - port does not participate in traffic forwarding and is not learning MAC addresses, is receiving BPDU `learning` - port does not participate in traffic forwarding, but is learning MAC addresses

Stats, Errors and Histogram

These menus provide detailed information about received and transmitted packets.

Note: Statistics for SFP+ interface are cleared whenever an active SFP+ link is established.

VLAN and VLANs

VLAN configuration for switch ports.

Property	Description
`VLAN Mode` (disabled \| optional \| enabled \| strict; Default: optional)	VLAN filtering mode, these options are relevant to egress ports (except for `strict` mode). `disabled` - VLAN table is not used. Switch discards packets with a VLAN tag on egress ports. If the packet has a VLAN tag and the VLAN ID matches `Default VLAN ID` on egress ports, then with `VLAN Receive=any` the switch will remove the VLAN tag and forward the packet. `optional` - Disabled VLAN filtering. Handle packets with VLAN tag ID that is not present in VLAN table just like packets without VLAN tag. `enabled` - Enabled VLAN filtering. Drop packets with VLAN tag ID that is not present in VLAN table. Default VLAN ID must be specified for access ports since it will be used to tag ingress traffic and untag egress traffic for the certain port. `strict` - Enabled VLAN filtering with additional ingress filtering, which checks if the ingress port is a member of the received VLAN ID in the VLAN table. Received packets on the ingress port with a VLAN ID that does not match with VLAN table will be dropped. Default VLAN ID must be specified for access ports since it will be used to tag ingress traffic and untag egress traffic for the certain port.
`VLAN Receive` (any \| only tagged \| only untagged; Default: optional)	Ingress traffic filtering based on VLAN tag presence. `any` - Allows tagged and untagged packets on a certain port `only tagged` - Allows only packets with a VLAN tag `only untagged` - Allows only packets without a VLAN tag
`Default VLAN ID` (integer: 1..4095; Default: 1)	VLAN ID which will be assigned on ingress traffic. Only has effect on untagged traffic, it will be ignored for tagged traffic. This parameter is usually used to allocate access ports with specific VLAN. It is also used to untag egress traffic if packet's VLAN ID matches Default VLAN ID.
`Force VLAN ID` (integer: yes \| no; Default: no)	Assigns the `Default VLAN ID` value to all ingress traffic (tagged and untagged). Has effect in all VLAN Modes. If port receives tagged traffic and `Default VLAN ID` is set to 1, then with this parameter the egress traffic will be untagged.

VLAN membership configuration for switch ports.

Property	Description
`VLAN ID` (integer: 1..4095; Default: 0)	VLAN ID to which assign ports.
`Port Isolation` (yes \| no; Default: yes)	Use settings from `Port Isolation` menu to isolate the defined VLAN to only certain ports. When disabled, the switch will ignore port isolation configuration and forward traffic with the defined VLAN ID only to ports that are checked as members.
`Learning` (yes \| no; Default: yes)	Enables or disables MAC address learning on the defined VLAN. If disabled, then all learned MAC addresses will appear as they have had been learned from VLAN 1.
`Mirror` (yes \| no; Default: no)	Enables or disables VLAN based mirroring. When enabled and `Mirror To` is set in the `Forwarding` menu, then all traffic from the defined VLAN will be mirrored to the selected port.
`IGMP Snooping` (yes \| no; Default: no)	Enables or disables IGMP Snooping on the defined VLAN. When enabled, the switch will listen to IGMP Join and Leave requests from the defined VLAN and only forward traffic to ports, which have sent IGMP membership requests from the defined VLAN. When disabled, the switch will flood all VLAN member ports with Multicast traffic.
`Members` (ports; Default: none)	Group of ports, which are allowed to forward traffic on the defined VLAN.

VLAN Configuration Example

Simple trunk and access port configuration example can be found at this article - CSS326-24G-2S+ Port Based VLAN

Hosts

This table represents dynamically learnt MAC address to port mapping entries. It can contain two kinds of entries: dynamic and static. Dynamic entries get added automatically, this is also called a learning process: when switch receives a packet from certain port, it adds the packet's source MAC address and port it received the packet from to host table, so when a packet comes in with certain destination MAC address it knows to which port it should forward the packet. If the destination MAC address is not present in host table then it forwards the packet to all ports in the group. Dynamic entries take about 5 minutes to time out. CRS3xx devices supports 16383 host table entries.

Static entries will take over dynamic if dynamic entry with same mac-address already exists. Also by adding a static entry you get access to some more functionality.

Property	Description
Ports	Ports the packet should be forwarded to
MAC	MAC address
VLAN ID	VLAN ID
Drop	Packet with certain MAC address coming from certain ports can be dropped
Mirror	Packet can be cloned and sent to mirror-target port

Property	Description
Port	Ports the packet should be forwarded to (Read-only)
MAC	Learned MAC address (Read-only)
VLAN ID	Learned VLAN ID (Read-only)

IGMP Snooping

IGMP Snooping which controls multicast streams and prevents multicast flooding is implemented in SwOS starting from version 2.5. The feature allows a switch to listen in the IGMP conversation between hosts and routers.

Enable this option under System tab.

Available IGMP snooping data can be found under IGMP tab:

It is possible to enable IGMP Snooping for a specific VLAN ID under VLANs menu.

Note: IGMP Snooping for VLANs requires enabled "Independent VLAN Lookup" in the System menu.

SNMP

SwOS supports SNMP v1 and uses IF-MIB, SNMPv2-MIB and BRIDGE-MIB for SNMP reporting.

Available SNMP data:

System information
System uptime
Port status
Interface statistics
Host table information

Property	Description
Enabled	Enable or disable SNMP service
Community	SNMP community name
Contact Info	Contact information for the NMS
Location	Location information for the NMS

ACL Tab

An access control list (ACL) rule table is very powerful tool allowing wire speed packet filtering, forwarding and VLAN tagging based on L2,L3 protocol header field conditions. Each rule contains a conditions part and an action part.

Conditions part parameters

Property	Description
From	Port that packet came in from
MAC Src	Source MAC address and mask
MAC Dst	Destination MAC address and mask
Ethertype	Protocol encapsulated in the payload of an Ethernet Frame
VLAN	VLAN header presence: any present not present
VLAN ID	VLAN tag ID
Priority	Priority in VLAN tag
IP Src (IP/netmask:port)	Source IPv4 address, netmask and L4 port number
IP Dst (IP/netmask:port)	Destination IPv4 address, netmask and L4 port number
Protocol (integer)	IP protocol
DSCP	IP DSCP field

Action part parameters

Property	Description
Redirect To	Force new packets destination port
Mirror	Clones packet and sends it to mirror-target port
Rate	Limits bandwidth (bps)
Drop	Drop packet
Set VLAN ID	Changes the VLAN tag ID, if VLAN tag is present
Priority	Changes the VLAN tag priority bits, if VLAN tag is present

Health

This menu provides different health related properties.

Property	Description
CPU Temperature	Shows CPU temperature in celsius temperature scale (Read-only)
Board Temperature	Shows PCB temperature in celsius temperature scale (Read-only)
FAN	Shows FAN rotational speed (Read-only)
PSU	Shows PSU related information depending on device model (Read-only): PSU state, either failed or ok (for CRS328-20S-4C-4S+, CRS317-1G-16S+) PSU voltage and consumed miliamperes by PoE-out connected devices (only for CRS328-24P-4S+)

Note: For devices with only a CPU temperature sensor (CRS326-24G-2S+, CRS305-1G-4S+, CRS309-1G-8S+) health information is available under System menu.

Dual Boot

“Dual Boot” feature allows you to choose which operating system you prefer to use, RouterOS or SwOS. Boot RouterOS option is under System tab:

Alternative Dual Boot possibilities: Dual Boot manual

Configuring SwOS using RouterOS

Since RouterOS 6.43 it is possible to load, save and reset SwOS configuration, as well as upgrade SwOS and set an IP address for the switch by using RouterOS.

Save configuration with /system swos save-config

Note: Configuration will be saved on the same device with swos.config as filename, make sure you download the file off your device since the configuration file will be removed after a reboot.

Load configuration with /system swos load-config

Reset configuration with /system swos reset-config

Set static IP address with /system swos set-address

Note: By setting a static IP address you are not changing the IP address acquisition process, which is DHCP with fallback by default. This means that the configured static IP address will become active only when there is going to be no DHCP servers in the same broadcast domain.

Upgrade SwOS from RouterOS using /system swos upgrade

Note: The upgrade command will automatically install the latest available SwOS version, make sure that your device has access to the Internet in order for the upgrade process to work properly.

Reset and Reinstall

With a reset button you can restore RouterOS default-configuration, from where you can configure SwOS using RouterOS.

CRS3xx devices with a serial console have some additional options.

To change between RouterOS and SwOS follow these steps:

Connect to the device using a serial console
Enter RouterBOOT setup
Chose "j - boot os"
Chose either RouterOS or SwOS

It is possible to load a SwOS backup firmware in case standard firmware breaks or upgrade fails:

Connect to the device using a serial console
Boot SwOS
Choose "p - boot primary SwOS"
After loading backup firmware, it is possible to connect to 192.168.88.1 using a web browser and install new SwOS firmware.

To reset SwOS configuration:

Connect to the device using a serial console
Boot SwOS
Choose "r - reset configuration"