Manual:Switch Chip Features
Applies to RouterOS: v6.0 +
Introduction
There are several types of switch chips on Routerboards and they have a different set of features. Most of them (from now on "Other") have only basic "Port Switching" feature, but there are few with more features:
Capabilities of switch chips:
| Feature | QCA8337 | Atheros8327 | Atheros8316 | Atheros8227 | Atheros7240 | ICPlus175D | MT7621 | RTL8367 | Other |
|---|---|---|---|---|---|---|---|---|---|
| Port Switching | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| Port Mirroring | yes | yes | yes | yes | yes | yes | yes | yes | no |
| TX limit | yes | yes | yes | yes | yes | no | no | no | no |
| RX limit | yes | yes | no | no | no | no | no | no | no |
| Host table | 2048 entries | 2048 entries | 2048 entries | 1024 entries | 2048 entries | no | 2048 entries | 2048 entries | no |
| Vlan table | 4096 entries | 4096 entries | 4096 entries | 4096 entries | 16 entries | no | no | no | no |
| Rule table | 92 rules | 92 rules | 32 rules | no | no | no | no | no | no |
Note: Cloud Router Switch (CRS) series devices have highly advanced switch chips built-in, they support wide variety of features. For more details about switch chip capabilities on CRS1xx/CRS2xx series devices check the CRS1xx/CRS2xx series switches manual, for CRS3xx series devices check the CRS3xx series switches manual.
| RouterBoard | Switch-chip description |
|---|---|
| RB4011iGS+ | RTL8367 (ether1-ether5); RTL8367 (ether6-ether10); |
| RB1100AHx4 | RTL8367 (ether1-ether5); RTL8367 (ether6-ether10); RTL8367 (ether11-ether13) |
| RB750Gr3 (hEX), RB760iGS (hEX S) | MT7621 (ether1-ether5) |
| RBM33G | MT7621 (ether1-ether3) |
| RB3011 series | QCA8337 (ether1-ether5); QCA8337 (ether6-ether10) |
| RB OmniTik ac series | QCA8337 (ether1-ether5) |
| RB941-2nD (hAP lite) | Atheros8227 (ether1-ether4) |
| RB951Ui-2nD (hAP); RB952Ui-5ac2nD (hAP ac lite); RB750r2 (hEX lite); RB750UPr2 (hEX PoE lite); RB750P-PBr2 (PowerBox); RB750P r2; RBOmniTikU-5HnDr2 (OmniTIK 5); RBOmniTikUPA-5HnDr2 (OmniTIK 5 PoE) | Atheros8227 (ether1-ether5) |
| RB750Gr2 (hEX); RB962UiGS-5HacT2HnT (hAP ac); RB960PGS (hEX PoE); RB960PGS-PB (PowerBox Pro) | QCA8337 (ether1-ether5) |
| RB953GS | Atheros8327 (ether1-ether3+sfp1) |
| RB850Gx2 | Atheros8327 (ether1-ether5) with ether1 optional [more] |
| RB2011 series | Atheros8327 (ether1-ether5+sfp1); Atheros8227 (ether6-ether10) |
| RB750GL; RB751G-2HnD; RB951G-2HnD; RBD52G-5HacD2HnD (hAP ac²) | Atheros8327 (ether1-ether5) |
| cAP ac | Atheros8327 (ether1-ether2) |
| RB1100AH | Atheros8327 (ether1-ether5); Atheros8327 (ether6-ether10) |
| RB1100AHx2 | Atheros8327 (ether1-ether5); Atheros8327 (ether6-ether10) |
| CCR1009 series | Atheros8327 (ether1-ether4) |
| RB493G | Atheros8316 (ether1+ether6-ether9); Atheros8316 (ether2-ether5) |
| RB435G | Atheros8316 (ether1-ether3) with ether1 optional [more] |
| RB450G | Atheros8316 (ether1-ether5) with ether1 optional [more] |
| RB450Gx4 | Atheros8327 (ether1-ether5) |
| RB433GL | Atheros8327 (ether1-ether3) |
| RB750G | Atheros8316 (ether1-ether5) |
| RB1200 | Atheros8316 (ether1-ether5) |
| RB1100 | Atheros8316 (ether1-ether5); Atheros8316 (ether6-ether10) |
| DISC Lite5 | Atheros8227 (ether1) |
| RBmAP2nD | Atheros8227 (ether1-ether2) |
| RBmAP2n | Atheros7240 (ether1-ether2) |
| RB750 | Atheros7240 (ether2-ether5) |
| RB750UP | Atheros7240 (ether2-ether5) |
| RB751U-2HnD | Atheros7240 (ether2-ether5) |
| RB951-2n | Atheros7240 (ether2-ether5) |
| RB951Ui-2HnD | Atheros8227 (ether1-ether5) |
| RB433 series | ICPlus175D (ether2-ether3); older models had ICPlus175C |
| RB450 | ICPlus175D (ether2-ether5); older models had ICPlus175C |
| RB493 series | ICPlus178C (ether2-ether9) |
| RB816 | ICPlus178C (ether1-ether16) |
Command line config is under /interface ethernet switch menu.
This menu contains a list of all switch chips present in system, and some sub-menus as well.
/interface ethernet switch menu list item represents a switch chip in system:
[admin@MikroTik] /interface ethernet switch> print Flags: I - invalid # NAME TYPE MIRROR-SOURCE MIRROR-TARGET 0 switch1 Atheros-8316 ether2 none
Depending on switch type there might be available or not available some configuration capabilities.
Atheros8316 packet flow diagram
Features
Port Switching
In order to setup port switching on non-CRS series devices, check the Bridge Hardware Offloading page.
Note: Port switching in RouterOS v6.41 and newer is done using the bridge configuration. Prior to RouterOS v6.41 port switching was done using the master-port property, for more details check the Master-port page.
Switch All Ports Feature
Ether1 port on RB450G/RB435G/RB850Gx2 has a feature that allows it to be removed/added to the default switch group. By default ether1 port will be included in the switch group. This configuration can be changed with /interface ethernet switch set switch1 switch-all-ports=no
- switch-all-ports=yes/no -
"yes" means ether1 is part of switch and supports switch grouping, and all other advanced Atheros8316/Atheros8327 features including extended statistics (/interface ethernet print stats).
"no" means ether1 is not part of switch, effectively making it as stand alone ethernet port, this way increasing its throughput to other ports in bridged, and routed mode, but removing the switching possibility on this port.
Port Settings
Properties under this menu are used to configure VLAN switching and filtering options for switch chips that support a VLAN Table. These properties are only available to switch chips that have VLAN Table support, check the Switch Chip Features table to make sure your device supports such a feature.
Warning: Ingress traffic is considered as traffic that is being sent IN a certain port, this port is sometimes called ingress port. Egress traffic is considered as traffic that is being sent OUT of a certain port, this port is sometimes called egress port. Distinguishing them is very important in order to properly set up VLAN filtering since some properties apply only to either ingress or egress traffic.
Sub-menu: /interface ethernet switch port
| Property | Description |
|---|---|
| vlan-mode (check | disabled | fallback | secure; Default: disabled) | Changes the VLAN lookup mechanism against the VLAN Table for ingress traffic.
|
| vlan-header (add-if-missing | always-strip | leave-as-is; Default: leave-as-is) | Sets action which is performed on the port for egress traffic.
|
| default-vlan-id (auto | integer: 0..4095; Default: auto) | Adds a VLAN tag with the specified VLAN ID on all untagged ingress traffic on a port, should be used with vlan-header set to always-strip on a port to configure the port to be the access port. For hybrid ports default-vlan-id is used to tag untagged traffic. If two ports have the same default-vlan-id, then VLAN tag is not added since the switch chip assumes that traffic is being forwarded between access ports. |
Note: Atheros8327 switch chips ignore the vlan-header property and uses the default-vlan-id property to determine which ports are access ports. For Atheros8327 switch chips the vlan-header is set to leave-as-is and cannot be changed while the default-vlan-id property should only be used on access ports to tag all ingress traffic.
VLAN Forwarding
Both vlan-mode and vlan-header along with the VLAN Table can be used to configure VLAN tagging, untagging and filtering, there are multiple combinations that are possible, each achieving a different result. Below you can find a table of what kind of traffic is going to be sent out through an egress port when a certain traffic is received on an ingress port for each VLAN Mode.
NOTES:
- L - vlan-header is set to
leave-as-is - S - vlan-header set to
always-strip - A - vlan-header set to
add-if-missing - U - Untagged traffic is sent out
- T - Tagged traffic is sent out, tag is already present on ingress port
- TA - Tagged traffic is sent out, tag was added on ingress port
- DI - Traffic is dropped on ingress port because of mode selected in vlan-mode
- DE - Traffic is dropped on egress port because egress port was not found in the VLAN Table
- VID match - VLAN ID from the VLAN tag for ingress traffic is present in the VLAN Table
- Port match - Ingress port is present in the VLAN Table for the appropriate VLAN ID
| VLAN Mode = disabled | Egress port not present in VLAN Table | Egress port is present in VLAN Table | ||||
|---|---|---|---|---|---|---|
| L | S | A | L | S | A | |
| Untagged traffic | U | U | TA | U | U | TA |
| Tagged traffic; no VID match | T | U | T | |||
| Tagged traffic; VID match; no Port match | T | U | T | T | U | T |
| Tagged traffic; VID match; Port match | T | U | T | T | U | T |
| VLAN Mode = fallback | Egress port not present in VLAN Table | Egress port is present in VLAN Table | ||||
|---|---|---|---|---|---|---|
| L | S | A | L | S | A | |
| Untagged traffic | U | U | TA | U | U | TA |
| Tagged traffic; no VID match | T | U | T | |||
| Tagged traffic; VID match; no Port match | DE | DE | DE | T | U | T |
| Tagged traffic; VID match; Port match | DE | DE | DE | T | U | T |
| VLAN Mode = check | Egress port not present in VLAN Table | Egress port is present in VLAN Table | ||||
|---|---|---|---|---|---|---|
| L | S | A | L | S | A | |
| Untagged traffic | ||||||
| Tagged traffic; no VID match | DI | DI | DI | |||
| Tagged traffic; VID match; no Port match | DE | DE | DE | T | U | T |
| Tagged traffic; VID match; Port match | DE | DE | DE | T | U | T |
| VLAN Mode = secure | Egress port not present in VLAN Table | Egress port is present in VLAN Table | ||||
|---|---|---|---|---|---|---|
| L | S | A | L | S | A | |
| Untagged traffic | ||||||
| Tagged traffic; no VID match | DI | DI | DI | |||
| Tagged traffic; VID match; no Port match | DI | DI | DI | DI | DI | DI |
| Tagged traffic; VID match; Port match | DE | DE | DE | T | U | T |
Note: The tables above are meant for more advanced configurations and to double check your own understand of how packets will be processed with each VLAN related property.
Port Mirroring
Port mirroring lets switch 'sniff' all traffic that is going in and out of one port (mirror-source) and send a copy of those packets out of some other port (mirror-target). This feature can be used to easily set up a 'tap' device that receives all traffic that goes in/out of some specific port. Note that mirror-source and mirror-target ports have to belong to same switch. (See which port belong to which switch in /interface ethernet menu). Also mirror-target can have a special 'cpu' value, which means that 'sniffed' packets should be sent out of switch chips cpu port. Port mirroring happens independently of switching groups that have or have not been set up.
- Port mirroring configuration example:
/interface ethernet switch set switch1 mirror-source=ether2 mirror-target=ether3
Warning: If you set mirror-source as a Ethernet port for a device with at least two switch chips and these mirror-source ports are in a single bridge while mirror-target for both switch chips are set to send the packets to the CPU, then this will result in a loop, which can make your device inaccessible.
Hosts Table
Basically the hosts table represents switch chips internal mac address to port mapping. It can contain two kinds of entries: dynamic and static. Dynamic entries get added automatically, this is also called a learning process: when switch chip receives a packet from certain port, it adds the packets 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. Learning is enabled only on ports that are configured as part of switch group. So you won't see dynamic entries if you have not set up port switching. Also you can add static entries that 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 that is controlled via following params:
- copy-to-cpu=yes/no - a packet can be cloned and sent to cpu port
- redirect-to-cpu=yes/no - a packet can be redirected to cpu port
- mirror=yes/no - a packet can be cloned and sent to mirror-target port configured in "/interface ethernet switch"
- drop=yes/no - a packet with certain mac address coming from certain ports can be dropped
copy-to-cpu, redirect-to-cpu, mirror actions are performed for packets which destination mac matches mac address specified in entry drop action is performed for packets which source mac address matches mac address specified in entry
Another possibility for static entries is that mac address can be mapped to more that one port, including 'cpu' port.
VLAN Table
VLAN table specifies certain forwarding rules for packets that have specific 802.1Q tag. Those rules are of higher priority than switch groups configured using the Bridge Hardware Offloading feature. 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 chip through one or more ports that are set in corresponding table entry. The exact logic that controls how packets with VLAN tags are treated is controlled by vlan-mode parameter that is changeable per switch port in /interface ethernet switch port menu.
Vlan-mode can take following values:
- disabled - ignore VLAN table, treat packet with VLAN tags just as if they did not contain a VLAN tag;
- fallback - the default mode - handle packets with VLAN tag that is not present in vlan table just like packets without VLAN tag. Packets with VLAN tags that are present in VLAN table, but incoming port does not match any port in VLAN table entry does not get dropped.
- check - drop packets with VLAN tag that is not present in VLAN table. Packets with VLAN tags that are present in VLAN table, but incoming port does not match any port in VLAN table entry does not get dropped.
- secure - drop packets with VLAN tag that is not present in VLAN table. Packets with VLAN tags that are present in VLAN table, but incoming port does not match any port in VLAN table entry get dropped.
VLAN tag id based forwarding takes into account the MAC addresses dynamically learned or manually added in the host table.
QCA8337 and Atheros8327 switch-chips also support Independent VLAN learning (IVL) which does the learning based on both MAC addresses and VLAN IDs thus allowing the same MAC to be used in multiple VLANs. The option "independent-learning" in VLAN table entries enables this feature.
Packets without VLAN tag are treated just like if they had a VLAN tag with port default-vlan-id. This means that if "vlan-mode=check or secure" to be able to forward packets without VLAN tags you have to add a special entry to VLAN table with the same VLAN ID set according to default-vlan-id.
Vlan-header option (configured in /interface ethernet switch port) sets the VLAN tag mode on egress port. Starting from RouterOS version 6 this option works with QCA8337, Atheros8316, Atheros8327, Atheros8227 and Atheros7240 switch chips and takes the following values:
- leave-as-is - packet remains unchanged on egress port;
- 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.
Rule Table
Rule table is very powerful tool allowing wire speed packet filtering, forwarding and vlan tagging based on L2,L3,L4 protocol header field condition.
Each rule contains a conditions part and an action part. Action part is controlled by following parameters:
- copy-to-cpu=yes/no - clones matching packets and sends them to cpu port;
- redirect-to-cpu=yes/no - redirects matching packets to cpu port;
- mirror=yes/no - clones matching packets and send them to mirror-target port;
- new-dst-ports - if set forces the destination port to be as specified, multiple ports allowed, including cpu port. Non obvious feature of this parameter is to pass empty list of ports to drop matching packets;
- new-vlan-id (only applies to Atheros8316) - if specified changes the vlan tag id, or add new vlan tag if one was not present;
- new-vlan-priority - if specified changes the vlan tag priority bits;
- rate (only applies to Atheros8327/QCA8337) - Sets limitation (bits per second) for all matched traffic. Can only be applied to first 32 rule slots.
Conditions part is controlled by rest of parameters:
- ports - match port that packet came in from (multiple ports allowed);
- mac layer conditions
- dst-mac-address - match by destination mac address and mask;
- src-mac-address - ...;
- vlan-header - match by vlan header presence;
- vlan-id (only applies to Atheros8316) - match by vlan tag id;
- vlan-priority (only applies to Atheros8316) - match by priority in vlan tag;
- mac-protocol - match by mac protocol (skips vlan tags if any);
- ip conditions
- dst-address - match by destination ip and mask;
- src-address - match by source ip and mask;
- dscp - match by ip dscp field;
- protocol - match by ip protocol;
- ipv6 conditions
- dst-address6 - match by destination ip and mask;
- src-address6 - match by source ip and mask;
- flow-label - match by ipv6 flow label;
- traffic-class - match by ipv6 traffic class;
- protocol - match by ip protocol;
- L4 conditions
- src-port - match by tcp/udp source port range;
- dst-port - match by tcp/udp destination port range;
IPv4 and IPv6 specific conditions cannot be present in same rule.
Menu contains ordered list of rules just like in /ip firewall filter.
Due to the fact that the rule table is processed entirely in switch chips hardware there is limitation to how many rules you may have. Depending on the amount of conditions (MAC layer, IP layer, IPv6, L4 layer) you use in your rules the amount of active rules may vary from 8 to 32 for Atheros8316 switch chip and from 24 to 96 for Atheros8327/QCA8337 switch chip. You can always do /interface ethernet switch rule print after modifying your rule set to see that no rules at the end of the list are 'invalid' which means those rules did not fit into the switch chip.
Port isolation
Port isolation provides the possibility to divide (isolate) certain parts of your network, this might be useful when need to make sure that certain devices cannot access other devices, this can be done by isolating switch ports. Switch port isolation is available on all switch chips since RouterOS v6.43.
Sub-menu: /interface ethernet switch port-isolation
| Property | Description |
|---|---|
| forwarding-override (interface; Default: ) | Forces ingress traffic to be forwarded to a specific interface. Multiple interfaces can be specified by separating them with a comma. |
Note: Port isolation is not compatible with (R/M)STP, you should only use protocol-mode=none. If (R/M)STP is running on the same bridge that is using port isolation, then (R/M)STP might fail to detect a loop or not properly elect a root bridge or root ports.
Warning: The forwarding-override property that has effect on ingress traffic only. Switch ports that do not have the forwarding-override specified are able to send packets through all switch ports.
Private VLAN
In some scenarios you might need to forward all traffic to a uplink port while all other ports are isolated from each other. This kind of setup is called Private VLAN configuration, the Switch will forward all Ethernet frames directly to the uplink port allowing the Router to filter unwanted packets and limit access between devices that are behind switch ports.
To configure switch port isolation, you need to switch all required ports:
/interface bridge add name=bridge1 /interface bridge port add interface=sfp1 bridge=bridge1 hw=yes add interface=ether1 bridge=bridge1 hw=yes add interface=ether2 bridge=bridge1 hw=yes add interface=ether3 bridge=bridge1 hw=yes
Note: By default, the bridge interface is configured with protocol-mode set to rstp. For some devices, this can disable hardware offloading because specific switch chips do not support this feature. See the Bridge Hardware Offloading section with supported features.
Override the egress port for each switch port that needs to be isolated (excluding the uplink port):
/interface ethernet switch port-isolation set ether1 forwarding-override=sfp1 set ether2 forwarding-override=sfp1 set ether3 forwarding-override=sfp1
Note: It is possible to set multiple uplink ports for a single switch chip, this can be done by specifying multiple interfaces and separating them with a comma.
Isolated switch groups
In some scenarios you might need to isolate a group of devices from other groups, this can be done using the switch port isolation feature. This is useful when you have multiple networks but you want to use a single switch, with port isolation you can allow certain switch ports to be able to communicate through only a set of switch ports. In this example devices on ether1-4 will only be able to communicate with devices that are on ether1-4, while devices on ether5-8 will only be able to communicate with devices on ether5-8 (ether1-4 is not able to communicate with ether5-8)
To configure isolated switch groups you must first switch all ports:
/interface bridge add name=bridge /interface bridge port add bridge=bridge1 interface=ether1 add bridge=bridge1 interface=ether2 add bridge=bridge1 interface=ether3 add bridge=bridge1 interface=ether4 add bridge=bridge1 interface=ether5 add bridge=bridge1 interface=ether6 add bridge=bridge1 interface=ether7 add bridge=bridge1 interface=ether8
Note: By default, the bridge interface is configured with protocol-mode set to rstp. For some devices, this can disable hardware offloading because specific switch chips do not support this feature. See the Bridge Hardware Offloading section with supported features.
Then specify in the forwarding-override property all ports that you want to be in the same isolated switch group (except the port on which you are applying the property), for example, to create an isolated switch group for A devices:
/interface ethernet switch port-isolation set ether1 forwarding-override=ether2,ether3,ether4 set ether2 forwarding-override=ether1,ether3,ether4 set ether3 forwarding-override=ether1,ether2,ether4 set ether4 forwarding-override=ether1,ether2,ether3
To create an isolated switch group for B devices:
/interface ethernet switch port-isolation set ether5 forwarding-override=ether6,ether7,ether8 set ether6 forwarding-override=ether5,ether7,ether8 set ether7 forwarding-override=ether5,ether6,ether8 set ether8 forwarding-override=ether5,ether6,ether7
CPU Flow Control
All switch chips have a special port that is called switchX-cpu, this is the CPU port for a switch chip, it is meant to forward traffic from a switch chip to the CPU, such a port is required for management traffic and for routing features. By default the switch chip ensures that this special CPU port is not congested and sends out Pause Frames when link capacity is exceeded to make sure the port is not oversaturated, this feature is called CPU Flow Control. Without this feature packets that might be crucial for routing or management purposes might get dropped.
Since RouterOS v6.43 it is possible to disable the CPU Flow Control feature on some devices that are using one of the follow switch chips: Atheros8227, QCA8337, Atheros8327, Atheros7240 or Atheros8316. Other switch chips have this feature enabled by default and cannot be changed. To disable CPU Flow Control use the following command:
/interface ethernet switch set switch1 cpu-flow-control=no
Statistics
Some switch chips are capable of reporting statistics, this can be useful to monitor how many packets are sent to the CPU from the built-in switch chip. These statistics can also be used to monitor CPU Flow Control. You can find an example of switch chip's statistics below:
[admin@MikroTik] > /interface ethernet switch print stats
name: switch1
driver-rx-byte: 221 369 701
driver-rx-packet: 1 802 975
driver-tx-byte: 42 621 969
driver-tx-packet: 310 485
rx-bytes: 414 588 529
rx-packet: 2 851 236
rx-too-short: 0
rx-too-long: 0
rx-broadcast: 1 040 309
rx-pause: 0
rx-multicast: 486 321
rx-fcs-error: 0
rx-align-error: 0
rx-fragment: 0
rx-control: 0
rx-unknown-op: 0
rx-length-error: 0
rx-code-error: 0
rx-carrier-error: 0
rx-jabber: 0
rx-drop: 0
tx-bytes: 44 071 621
tx-packet: 312 597
tx-too-short: 0
tx-too-long: 8 397
tx-broadcast: 2 518
tx-pause: 2 112
tx-multicast: 7 142
tx-excessive-collision: 0
tx-multiple-collision: 0
tx-single-collision: 0
tx-excessive-deferred: 0
tx-deferred: 0
tx-late-collision: 0
tx-total-collision: 0
tx-drop: 0
tx-jabber: 0
tx-fcs-error: 0
tx-control: 2 112
tx-fragment: 0
tx-rx-64: 6 646
tx-rx-65-127: 1 509 891
tx-rx-128-255: 1 458 299
tx-rx-256-511: 178 975
tx-rx-512-1023: 953
tx-rx-1024-1518: 672
tx-rx-1519-max: 0
Some devices have multiple CPU cores that are directly connected to a built-in switch chip using separate data lanes. These devices can report which data lane was used to forward the packet from or to the CPU port from the switch chip. For such devices an extra line is added for each row, the first line represents data that was sent using the first data lane, the second line represent data that was sent using the second data line and so on. You can find an example of switch chip's statistics for a device with multiple data lanes connecting the CPU and the built-in switch chip:
[admin@MikroTik] > /interface ethernet switch print stats
name: switch1
driver-rx-byte: 226 411 248
0
driver-rx-packet: 1 854 971
0
driver-tx-byte: 45 988 067
0
driver-tx-packet: 345 282
0
rx-bytes: 233 636 763
0
rx-packet: 1 855 018
0
rx-too-short: 0
0
rx-too-long: 0
0
rx-pause: 0
0
rx-fcs-error: 0
0
rx-overflow: 0
0
tx-bytes: 47 433 203
0
tx-packet: 345 282
0
tx-total-collision: 0
0
Setup Examples
Note: Make sure you have added all needed interfaces to the VLAN table when using secure vlan-mode. For routing functions to work properly on the same device through ports that use secure vlan-mode, you will need to allow access to the CPU from those ports, this can be done by adding the switchX-cpu interface itself to the VLAN table. Examples can be found at the Management port section.
Warning: When allowing access to the CPU, you are allowing access from a certain port to the actual router/switch, this is not always desirable. Make sure you implement proper firewall filter rules to secure your device when access to the CPU is allowed from a certain VLAN ID and port, use firewall filter rules to allow access to only certain services.
Note: It is possible to use the built-in switch chip and the CPU at the same time to create a Switch-Router setup, where a device acts as a switch and as a router at the same time. You can find a configuration example in the Switch-Router guide.
VLAN Example 1 (Trunk and Access Ports)
RouterBOARDs with Atheros switch chips can be used for 802.1Q Trunking. This feature in RouterOS v6 is supported by QCA8337, Atheros8316, Atheros8327, Atheros8227 and Atheros7240 switch chips.
In this example ether3, 'ether4 and ether5 interfaces are access ports, while ether2 is a trunk port. VLAN IDs for each access port: ether3 - 200, ether4 - 300, ether5 - 400.
Switch together the required ports:
/interface bridge add name=bridge1 /interface bridge port add bridge=bridge1 interface=ether2 hw=yes add bridge=bridge1 interface=ether3 hw=yes add bridge=bridge1 interface=ether4 hw=yes add bridge=bridge1 interface=ether5 hw=yes
Note: By default, the bridge interface is configured with protocol-mode set to rstp. For some devices, this can disable hardware offloading because specific switch chips do not support this feature. See the Bridge Hardware Offloading section with supported features.
Add VLAN table entries to allow frames with specific VLAN IDs between ports:
/interface ethernet switch vlan add ports=ether2,ether3 switch=switch1 vlan-id=200 add ports=ether2,ether4 switch=switch1 vlan-id=300 add ports=ether2,ether5 switch=switch1 vlan-id=400
Assign vlan-mode and vlan-headermode for each port and also default-vlan-id on ingress for each access port:
/interface ethernet switch port set ether2 vlan-mode=secure vlan-header=add-if-missing set ether3 vlan-mode=secure vlan-header=always-strip default-vlan-id=200 set ether4 vlan-mode=secure vlan-header=always-strip default-vlan-id=300 set ether5 vlan-mode=secure vlan-header=always-strip default-vlan-id=400
- Setting
vlan-mode=secureensures strict use of VLAN table. - Setting
vlan-header=always-stripfor access ports removes VLAN header from frame when it leaves the switch chip. - Setting
vlan-header=add-if-missingfor trunk port adds VLAN header to untagged frames. - default-vlan-id specifies what VLAN ID is added for untagged ingress traffic of the access port.
VLAN Example 2 (Trunk and Hybrid Ports)
VLAN Hybrid ports which can forward both tagged and untagged traffic are supported only by some Gigabit switch chips (QCA8337, Atheros8327)
Switch together the required ports:
/interface bridge add name=bridge1 /interface bridge port add bridge=bridge1 interface=ether2 hw=yes add bridge=bridge1 interface=ether3 hw=yes add bridge=bridge1 interface=ether4 hw=yes add bridge=bridge1 interface=ether5 hw=yes
Note: By default, the bridge interface is configured with protocol-mode set to rstp. For some devices, this can disable hardware offloading because specific switch chips do not support this feature. See the Bridge Hardware Offloading section with supported features.
Add VLAN table entries to allow frames with specific VLAN IDs between ports.
/interface ethernet switch vlan add ports=ether2,ether3,ether4,ether5 switch=switch1 vlan-id=200 add ports=ether2,ether3,ether4,ether5 switch=switch1 vlan-id=300 add ports=ether2,ether3,ether4,ether5 switch=switch1 vlan-id=400
In switch port menu set vlan-mode on all ports and also default-vlan-id on planned hybrid ports:
/interface ethernet switch port set ether2 vlan-mode=secure vlan-header=leave-as-is set ether3 vlan-mode=secure vlan-header=leave-as-is default-vlan-id=200 set ether4 vlan-mode=secure vlan-header=leave-as-is default-vlan-id=300 set ether5 vlan-mode=secure vlan-header=leave-as-is default-vlan-id=400
vlan-mode=securewill ensure strict use of VLAN table.- default-vlan-id will define VLAN for untagged ingress traffic on port.
- In Gigabit switch chips when
vlan-mode=secure, it ignores switch port vlan-header options. VLAN table entries handle all the egress tagging/untagging * and works asvlan-header=leave-as-ison all ports. - It means what comes in tagged, goes out tagged as well, only default-vlan-id frames are untagged at the egress of port.
Management access configuration
In these examples there will be shown examples for multiple scenarios, but each of these scenarios require you to have switched ports. Below you can find how to switch multiple ports:
/interface bridge add name=bridge1 /interface bridge port add interface=ether1 bridge=bridge1 hw=yes add interface=ether2 bridge=bridge1 hw=yes
Note: By default, the bridge interface is configured with protocol-mode set to rstp. For some devices, this can disable hardware offloading because specific switch chips do not support this feature. See the Bridge Hardware Offloading section with supported features.
In these examples it will be assumed that ether1 is the trunk port and ether2 is the access port, for configuration as the following:
/interface ethernet switch port set ether1 vlan-header=add-if-missing set ether2 default-vlan-id=100 vlan-header=always-strip /interface ethernet switch vlan add ports=ether1,ether2,switch1-cpu switch=switch1 vlan-id=100
Tagged
In order to make the device accessible only from a certain VLAN, you need to create a new VLAN interface on the bridge interface and assign an IP address to it:
/interface vlan add name=MGMT vlan-id=99 interface=bridge1 /ip address add address=192.168.99.1/24 interface=MGMT
Specify from which interfaces it is allowed to access the device:
/interface ethernet switch vlan add ports=ether1,switch1-cpu switch=switch1 vlan-id=99
Note: Only specify trunk ports in this VLAN table entry, it is not possible to allow access to the CPU with tagged traffic through an access port since the access port will tag all ingress traffic with the specified default-vlan-id value.
When VLAN table is configured, you can enable vlan-mode=secure to limit access to the CPU:
/interface ethernet switch port set ether1 vlan-header=add-if-missing vlan-mode=secure set ether2 default-vlan-id=100 vlan-header=always-strip vlan-mode=secure set switch1-cpu vlan-header=leave-as-is vlan-mode=secure
Untagged
In order to make the device accessible from the access port, create a VLAN interface with the same VLAN ID as set in default-vlan-id, for example VLAN 100, and add an IP address to it:
/interface vlan add name=VLAN100 vlan-id=100 interface=bridge1 /ip address add address=192.168.100.1/24 interface=VLAN100
Specify which access (untagged) ports are allowed to access the CPU:
/interface ethernet switch vlan add ports=ether1,ether2,switch1-cpu switch=switch1 vlan-id=100
Warning: Most commonly an access (untagged) port is accompanied with a trunk (tagged) port. In case of untagged access to the CPU, you are forced to specify both the access port and the trunk port, this gives access to the CPU from the trunk port as well. Not always this is desired and Firewall might be required on top of VLAN filtering.
When VLAN table is configured, you can enable vlan-mode=secure to limit access to the CPU:
/interface ethernet switch port set ether1 vlan-header=add-if-missing vlan-mode=secure set ether2 default-vlan-id=100 vlan-header=always-strip vlan-mode=secure set switch1-cpu vlan-header=leave-as-is vlan-mode=secure
Untagged from tagged port
It is possible to allow access to the device from the trunk (tagged) port with untagged traffic. To do so, assign an IP address on the bridge interface:
/ip address add address=10.0.0.1/24 interface=bridge1
Specify the trunk port to be able to access the CPU for the default-vlan-id for the trunk port, by default it is set to 1:
/interface ethernet switch vlan add ports=ether1,switch1-cpu switch=switch1 vlan-id=1
When VLAN table is configured, you can enable vlan-mode=secure to limit access to the CPU:
/interface ethernet switch port set ether1 default-vlan-id=1 vlan-header=add-if-missing vlan-mode=secure set switch1-cpu vlan-header=leave-as-is vlan-mode=secure