Hitless Behavior - Dell C9000 Series Networking Configuration Manual

Current Type : C9000LC0640 - 6-port TE/FG
Hardware Rev : 4.0
Num Ports : 24
Up Time : 0 sec
Dell Networking OS Version : 1-0(0-4079)
Jumbo Capable : yes
POE Capable : Not supported
Max Required Power : 125
Boot Flash : 3.3.1.15
Boot Selector : 3.3.0.0g
Memory Size : 2127654912 bytes
Serial Number :
Part Number : 0CYFF2 Rev X00
Vendor Id :
Date Code :
Country Code :
Piece Part ID : CN-0CYFF2-77931-49G-0009
PPID Revision : X00
Service Tag : 14CRG02
Expr Svc Code : 244 008 288 2
Auto Reboot : enabled
Last Restart : powered-on
Burned In MAC : 34:17:eb:01:8c:00
No Of MACs : 3

Hitless Behavior

Hitless is a protocol-based system behavior in a dual-RPM chassis that is transparent to remote systems. In
the event of a control-plane failover, it is not necessary to notify the remote systems of a local state change.
Hitless protocols are compatible with other hitless and graceful restart protocols. A software or hardware
exception may trigger hitless failovers, or a forced failover using the command line interface (CLI).
For example, if you configure hitless open shortest path first (OSPF) over hitless the link aggregation control
protocol (LACP) link aggregation groups (LAGs), both features work seamlessly to deliver a hitless OSPF-LACP
result. However, to achieve a hitless result, if the hitless behavior involves multiple protocols, all protocols
must be hitless. For example, if OSPF is hitless but bidirectional forwarding detection (BFD) is not, OSPF
operates in hitless mode and BFD flaps upon a control-plane failover.
The following protocols are hitless:
• 802.1X (802.1X)
• Bidirectional Forwarding Detection
• Internet Group Management Protocol
IGMP Snooping)
• Link aggregation control protocol
• Link layer discovery protocol
• Spanning tree protocol
(Bidirectional Forwarding Detection
(Internet Group Management Protocol (IGMP)
(Link Aggregation Control Protocol
(Link Layer Discovery Protocol
(Spanning Tree Protocol
(LACP))
(LLDP))
(STP))
(BFD))
and
High Availability (HA) 471