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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 have their own firmware which cannot be installed on other series models! New RB260GS (CSS106-5G-1S), new RB260GSP(CSS106-1G-4P-1S) supports SwOS v2.0 and newer. When upgrading the device, it will first load primary firmware and then make an upgrade. In case a wrong firmware file is chosen, the device will continue to operate with primary firmware and you will be able to choose the correct file.

CSS106 series features

  • Full non-blocking wirespeed switching
  • Up to 2k MAC entries in Host table
  • Forwarding Database works based on SVL or IVL
  • Port Isolation
  • Port Lock
  • Jumbo frame support - 9198 bytes
Spanning Tree Protocol
  • RSTP support
Multicast Forwarding
  • IGMP Snooping support
  • Port based mirroring
  • Fully compatible with IEEE802.1Q
  • Port based VLAN
  • VLAN filtering
Quality of Service (QoS)
  • Ingress traffic limiting (by ACL)
  • Egress 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

Connecting to the Switch

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

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SwOS Login

SwOS default IP address:, 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 several tabs: Link, SFP, Forwarding, RST, Statistics, Errors, VLAN, VLANs, Hosts, IGMP Groups, SNMP, ACL, System 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 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.

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General settings

Property Description
Address AcquisitionSpecify 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 AddressIP address of the switch in case of Address Acquisition is set as DHCP with fallback or static
IdentityName of the Switch (for Mikrotik neighbor discovery protocol)
Allow FromIP address from which the service is accessible. Default value is '' - any address
Allow From PortsList of switch ports from which the service is accessible
Allow From VLANVLAN ID with which the service is accessible (VLAN Mode on ingress port must be other than disabled in order to connect)
WatchdogEnable or disable system watchdog. It will reset CPU of the switch in case of fault condition
Independent VLAN LookupEnable or disable independent VLAN lookup in the Host table for packet forwarding
IGMP SnoopingEnable or disable IGMP Snooping
Mikrotik Discovery ProtocolEnable or disable Mikrotik neighbor discovery protocol
Port1 PoE In Long CableIf enabled, it will turn off short detection on all PoE out ports to allow use of longer ethernet cables. This is potentially dangerous setting and should be used with caution. (CSS106-1G-4P-1S model)
MAC AddressMAC address of the Switch (Read-only)
Serial NumberSerial number of the switch (Read-only)
Board NameMikroTik model name of the switch (CSS106 model, Read-only)

Health (CSS106-1G-4P-1S)

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CSS106-1G-4P-1S Health settings

Property Description
VoltageShows the input voltage measured in volts
TemperatureShows PCB temperature in celsius temperature scale

Password and Backup

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CSS106 System Management Settings


Link Tab allows you to:

  • Configure Ethernet and SFP ports
  • Monitor status of Ethernet and SFP ports

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Link settings

Property Description
EnabledEnable or disable port
NameEditable port name
Link StatusCurrent link status (Read-only)
Auto NegotiationEnable or disable auto negotiation (some SFP modules may required it disabled in order to work)
SpeedSpecify speed setting of the port (requires auto negotiation to be disabled)
Full DuplexSpecify duplex mode of the port (requires auto negotiation to be disabled)
Flow control Enable or disable 802.3x Flow control

Note: Using SFP+ 1m/3m DAC cable or S-RJ01 module, the device always shows that link is established even if nothing is connected on other end.

PoE (CSS106-1G-4P-1S)

PoE settings configure Power over Ethernet output on CSS106-1G-4P-1S port2-port5 and show PoE status and measurements.

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CSS106-1G-4P-1S PoE Out settings

Property Description
PoE Out

Sets PoE out mode of the port:

  • off - all detection and PoE out is turned off
  • auto - detection is done regarding resistance on the spare pairs to check if port has PoE capability. For port to be turned on measured value should be within range from 3kΩ to 26.5kΩ
  • on - PoE out is enabled regardless of the resistance on the port. Use this with caution as that can damage connected equipment!
  • calibr - manual port PoE out recalibration. It may be necessary if there are ocasional problems with powering connected devices.
PoE PriorityPort priority for PoE out supply. If installation is going over power budged, port with the lowest priority is going to be turned off first. 1 - the highest priority port; 4 - the lowest priority port
PoE Status

Current PoE out status of the port:

  • disabled - PoE out is turned off
  • waiting for load - "auto" mode detects out of range resistance to turn on PoE out
  • powered on - PoE out is turned on
  • short circuit - if it is detected, to ensure that there is no additional damage on powered device and no damage on powering device PoE out is turned off
  • voltage too low - not enough voltage supplied to turn on device with PoE out
  • current too low - not enough current supplied to turn on device with PoE out
  • waiting for cable disconnect - manual recalibration with "calibr" has detected connected device and waits for disconnection to complete the recalibration process
PoE CurrentShows current usage on the port measured in miliamperes
PoE PowerShows PoE out power on the port measured in watts


SFP tab allows you to monitor status of SFP modules.

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Forwarding Tab provides advanced forwarding options among switch ports, port isolation, port locking, port mirroring and egress bandwidth limit features.

Ingress rate per port as well as rate for broadcast traffic can be configured with Access Control List by setting Rate. ACL must have one port per entry to provide bandwidth limiting properly.

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Forwarding settings

Property Description
ForwardingForwarding table - allows or restricts traffic flow between specific ports
Port Lock
  • Port Lock - Enables or disables MAC address learning on this port. When option is enabled, it will restrict MAC address learning and static MAC addresses should be configured
  • Lock On First - enable or disable MAC address learning on this port (MAC address from the first recieved 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
Bandwidth Limit
  • Egress Rate - limit traffic leaving this port (bps)


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

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CSS106 RSTP Settings

Property Description
RSTPEnable or disable STP/RSTP functionality on this port
Mode Shows STP/RSTP functionality mode on specific port (Read-only):
  • RSTP
  • STP
RoleShows 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 CostShows root path cost for ports that are facing root bridge (Read-only)
  • 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)
StateShows 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
Property Description
Bridge Priority (hex)RSTP bridge priority for Root Bridge selection
Port Cost ModeThere 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 BridgeThe priority and MAC address of the selected Root Bridge in the network (Read-only)

Statistics, Errors

Provides detailed information about received and transmitted packets.

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Port statistics

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Port errors


VLAN configuration for Switch ports.

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VLAN settings

Property Description

VLAN mode for ingress port:

  • disabled - VLAN table is not used. Switch ignores VLAN tag part of tagged packets
  • optional - Handle packets with VLAN tag ID that is not present in VLAN table just like packets without VLAN tag
  • enabled - Drop packets with VLAN tag ID that is not present in VLAN table. Packets without VLAN tag are treat as tagged packets with Default VLAN ID
  • strict - Same as enable, but also checks VLAN support for inbound interface (drop packets with VLAN tag ID and ingress port that are not present in VLAN table)
VLAN ReceiveDefines the type of allowed packets on ingress port:
  • 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 IDSwitch will treat both untagged and "Default VLAN ID" tagged ingress packets as they are tagged with this VLAN ID. It is also used to untag egress traffic if packet's VLAN ID matches "Default VLAN ID". The VLAN tag itself will only be added if there is VLAN Header = add if missing specified on egress port
Force VLAN IDWhether to apply Default VLAN ID to incoming packets with VLAN tag
VLAN Header
  • leave as is - if VLAN header is present it remains unchanged
  • always strip - if VLAN header is present it is removed from the packet
  • add if missing - if VLAN header is not present it is added to the packet (VLAN ID will be Default VLAN ID of ingress port)

Note: VLAN modes enabled and strict require VLAN ID 1 in VLANs table to allow access of untagged traffic to switch itself.

VLAN Configuration Examples

Simple trunk and access port configuration, as well as trunk and hybrid port configuration examples can be found in this article - SwOS/CSS106-VLAN-Example.


VLAN tables specifies certain forwarding rules for packets that have specific IEEE 802.1Q tag. Basically the table contains entries that map specific VLAN tag IDs to a group of one or more ports. Packets with VLAN tags leave switch through one or more ports that are set in corresponding table entry. VLAN table works together with destination MAC lookup to determine egress ports. VLAN table supports up to 250 entries.

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CSS106 VLANs settings

Property Description
VLAN IDVLAN ID of the packet
IVLEnables or disables independent VLAN learning (IVL)
IGMP SnoopingEnables 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.
PortsEach port has individual VLAN header options for each VLAN ID. Depending on VLAN mode if lookup is done in this table, egress action of packets is processed by this option. Egress option from VLAN tab is ignored.


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 X and port it received the packet from to host table, so when a packet comes in with destination MAC address X 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.


Note: CSS106 series switches support 2048 host table entries.

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Host table

Property Description
PortPorts the packet should be forwarded to (Read-only)
MACLearned MAC address (Read-only)
VLAN IDLearned VLAN ID (Read-only)

Static Hosts

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.

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Static host table

Property Description
PortsPorts the packet should be forwarded to
MACMAC address
VLAN IDVLAN ID (only supported on RB260GS/RB260GSP)
DropPacket with certain MAC address coming from certain ports can be dropped
MirrorPacket can be cloned and sent to mirror-target port

IGMP Groups

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.

First, enable option under System tab.

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IGMP Snooping under System tab

Available IGMP snooping data can be found under IGMP Group tab:

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CSS106 series IGMP Snooping

Possibility to enable IGMP Snooping for specific VLAN ID.

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CSS106 series IGMP Snooping


SwOS supports SNMP v1 and uses IF-MIB, SNMPv2-MIB, BRIDGE-MIB and MIKROTIK-MIB (only for health, PoE-out and SFP diagnostics) for SNMP reporting.

Available SNMP data:

  • System information
  • System uptime
  • Port status
  • Interface statistics
  • Host table information
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SNMP settings

Property Description
EnabledEnable or disable SNMP service
CommunitySNMP community name
Contact InfoContact information for the NMS
LocationLocation information for the NMS


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. SwOS allow you to implement limited number of access control list rules (32 simple rules (only L2 conditions are used); 16 rules where both L2 and L3 conditions are used; or 8 advanced rules where all L2,L3 and L4 conditions are used). Each rule contains a conditions part and an action part.

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Access Control List settings

Conditions part parameters

Property Description
FromPort that packet came in from
MAC SrcSource MAC address and mask
MAC DstDestination MAC address and mask
EthertypeProtocol encapsulated in the payload of an Ethernet Frame

VLAN header presence:

  • any
  • present
  • not present
PriorityPriority 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
ProtocolIP protocol

Action part parameters

Property Description
Redirect ToWhether to force new destination ports (If Redirect To is enabled and no ports specified in Redirect To Ports, packet will be dropped )
Redirect To PortsDestination ports for
MirrorClones packet and sends it to mirror-target port
RateLimits bandwidth (bps)
Set VLAN IDChanges the VLAN tag ID, if VLAN tag is present
PriorityChanges the VLAN tag priority bits, if VLAN tag is present


The CSS106-5G-1S and CSS106-1G-4P-1S has built-in backup SwOS firmware which can be loaded in case standard firmware breaks or upgrade fails:

  • Holding Reset button for few seconds while device is booting resets configuration and loads backup firmware SwOS 2.0p.
  • After loading backup firmware SwOS 2.0p it is possible to connect to using web browser and install new SwOS firmware.