Manual:Fast Path
Applies to RouterOS: v6.0rc2 +
Summary
Fast path allows to forward packets without additional processing in the Linux kernel. It improves forwarding speeds significantly.
For fast path to work, interface support and specific configuration conditions are required.
List of RouterBoards with FastPath support
| RouterBoard | Interfaces |
|---|---|
| RB6xx series | ether1,2 |
| RB7xx series | all ethernets |
| RB8xx series | ether1,2 |
| RB9xx series | all ethernets |
| RB1000 | all ethernets |
| RB1100 series | ether1-10,11 |
| RB2011 series | all ethernets and sfp |
| CCR series routers | all ethernets and sfps |
FastPath Handlers
Currently RouterOS has following fast path handlers:
- ipv4
- traffic generator
- mpls
- bridge
Note: Packet will be forwarded in fast path only if source and destination interfaces support fast path. See the list of supported interfaces.
IPv4 handler
IPv4 fast path is automatically used if following conditions are met:
- firewal rules are not configured,
- Traffic flow is disabled
/ip traffic-flow enabled=no - Simple and queue trees with parent=global are not configured.
- source interface is not bridge port or bonding slave
- destination interface queue is set to only-hw-queue and no queue tree entries with parent="dst interface"
- no mesh, metarouter interface configuration,
- sniffer, torch and traffic generator is not running
- connection tracking is not active
- ip accounting is disabled (/ip accounting enabled=no);
- VRFs are not set (/ip route vrf is empty);
- Hotspot is not used (/ip hostspot has no interfaces);
- IpSec policies are not configured (ROS v6.8)
/ip firewall connection tracking set enabled parameter has new auto value Which means that connection tracking is disabled by default until firewall rules are added.
Note: Starting from v6.1 added VRRP interface no longer disables fast path globally. Ipv4 and bridge fast path handlers will not work only if source interface is vrrp slave interface.
Traffic Generator handler
Traffic Generator fast path is automatically used for interfaces that support this feature.
MPLS handler
MPLS fast path is automatically used for interfaces that support this feature.
Currently MPLS fast-path applies only to MPLS switched traffic (frames that enter router as MPLS and must leave router as MPLS) - MPLS ingress and egress (including VPLS tunnel endpoints that do VPLS encap/decap) will operate as before.
Bridge handler
Bridge fast path is automatically used if following conditions are met:
- no bridge firewall rules (
/interface bridge filter, /interface bridge nat) are configured, /interface bridge settings use-ip-firwall=no,- destination interface queue is set to only-hw-queue,
- no mesh, metarouter interface configuration,
- sniffer, torch and traffic generator is not running
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