Hitless Behavior
Hitless is a protocol-based system behavior that makes a stack unit failover on the local system transparent to
remote systems. The system synchronizes protocol information on the Management and Standby stack units
such that, in the event of a stack unit failover, it is not necessary to notify the remote systems of a local state
change.
Hitless behavior is defined in the context of a stack unit failover only.
• Only failovers via the CLI are hitless. The system is not hitless in any other scenario.
Hitless protocols are compatible with other hitless and graceful restart protocols. For example, if hitless open
shortest path first (OSPF) is configured 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 end 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 hitlessly and
BFD flaps upon an RPM failover.
The following protocols are hitless:
• Link aggregation control protocol.
• Spanning tree protocol. Refer to
Configuring Spanning Trees as Hitless
.
Graceful Restart
Graceful restart (also known as non-stop forwarding) is a protocol-based mechanism that preserves the
forwarding table of the restarting router and its neighbors for a specified period to minimize the loss of
packets. A graceful-restart router does not immediately assume that a neighbor is permanently down and so
does not trigger a topology change. Packet loss is non-zero, but trivial, and so is still called hitless.
Dell Networking OS supports graceful restart for the following protocols:
• Border gateway
• Open shortest path first
• Protocol independent multicast — sparse mode
• Intermediate system to intermediate system
High Availability (HA)
422
Содержание S4048T
Страница 1: ...Dell Configuration Guide for the S4048T ON System 9 10 0 1 ...
Страница 98: ... saveenv 7 Reload the system uBoot mode reset Management 98 ...
Страница 113: ...Total CFM Pkts 10303 CCM Pkts 0 LBM Pkts 0 LTM Pkts 3 LBR Pkts 0 LTR Pkts 0 802 1ag 113 ...
Страница 411: ...mode transit no disable Force10 Resilient Ring Protocol FRRP 411 ...
Страница 590: ...Figure 67 Inspecting the LAG Configuration Link Aggregation Control Protocol LACP 590 ...
Страница 591: ...Figure 68 Inspecting Configuration of LAG 10 on ALPHA Link Aggregation Control Protocol LACP 591 ...
Страница 594: ...Figure 70 Inspecting a LAG Port on BRAVO Using the show interface Command Link Aggregation Control Protocol LACP 594 ...
Страница 595: ...Figure 71 Inspecting LAG 10 Using the show interfaces port channel Command Link Aggregation Control Protocol LACP 595 ...
Страница 646: ...Figure 87 Configuring Interfaces for MSDP Multicast Source Discovery Protocol MSDP 646 ...
Страница 647: ...Figure 88 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 647 ...
Страница 648: ...Figure 89 Configuring PIM in Multiple Routing Domains Multicast Source Discovery Protocol MSDP 648 ...
Страница 653: ...Figure 91 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 653 ...
Страница 654: ...Figure 92 MSDP Default Peer Scenario 3 Multicast Source Discovery Protocol MSDP 654 ...
Страница 955: ...Figure 119 Single and Double Tag First byte TPID Match Service Provider Bridging 955 ...
Страница 1179: ...Figure 147 Create Hypervisor Figure 148 Edit Hypervisor Figure 149 Create Transport Connector Virtual Extensible LAN VXLAN 1179 ...