High Availability Flashcards
Graceful restart works by informing OSPF neighbors that it is going to restart. The router that is going to restart is called the _________________
restarting router
(OSPF) the restarting process is called the _____________
graceful restart mode
Graceful restart initiate by sending a link-local type _ LSA called the grace LSA with a specified time called the ________
9 grace period
Two adjancent routers enter helper mode and are called the __________
helper neighbors
OSPF graceful restart is covered in RFC 3623.. Before the RFC, Cisco already implemented its own version of graceful restart called ___________ . Cisco IOS supports both NSF and the RFC version of graceful restart.
NSF (Non-Stop Forwarding)
Graceful shutdown - Its possible to shutdown OSPF process using ________ command and at interface level you may use _______ command
Shutdown, ip ospf shutdown
MPLS LDP GR functions strictly in ______ ____, which means it can only help other routers that are enabled with MPLS SSO/NSF and GR to recover. If the router with LDP GR fails, its peer routers cannot help it recover.
helper mode
A operação básica do LDP GR /NSF é a mesma dos demais protocolos. Os routers contnuam encaminhando pacotes mesmo após a queda da adjacência LDP.
Verdadeiro
Uma adjancencia entre router LDP GR > LDP SSO/NSF > LDP GR é inválida
falso, é verdadeiro
Quando ocorre uma falha e LDP GR/NSF está ativado as entradas na LFIB são marcadas como stale, após a recuperação da sessão LDP a flag é removida
verdadeiro
O Router anuncia o GR capable via flag Fault Tolerant durante o estabelecimento da sessão
parcialmente falso, o anúncio é via TLV FT e não flag
- MPLS LDP GR is supported in _________.
- ________________ sessions are not supported. Only LDP sessions are supported.
- MPLS LDP GR cannot be configured on label-controlled ___ (LC-___) interfaces.
strict helper mode
Tag Distribution Protocol (TDP)
ATM
MPLS LDP GR conf:
SUMMARY STEPS
1. enable
- configure terminal
- ip cef [distributed]
- __________________
mpls ldp graceful-restart
control plane could stop functioning altogether and because the forwarding plane is a separate entity with its own processors it can continue forwarding packets based on its copy of the FIB. This is ________ ______ ______ (_ _ _): The ability of the forwarding plane to continue running “headless” if the control plane stops.
Non-Stop Forwarding (NSF)
_ _ _ allows you to switch from a primary to a backup control plane without disrupting forwarding. The FIB could still become invalid during the period between when the primary control plane goes down and the backup control plane takes over, but the risk in this period is usually an acceptable compromise
NSF
the backup control plane maintains a copy of the active configuration and current state on system components such as interfaces, it can become active much faster than if it had to learn all this information first. That, then, is the second ring of our acronym circus: Cisco calls this ____ ____ ____ (_ _ _)
Stateful Switchover (SSO)
Descreva em resumidamente a função do Non Stop Routing e do graceful restart
Ambos tem por objetivo prevenir a reconvergencia de protocolos de roteamento
Eles mantem o roteamento acontecendo durante um switchover de RP
O NSR está disponível para quais protocolos ?
Apenas isis e bgp
Para quais protocolos o graceful restart está disponível ?
OSPF, BGP, ISIS, LDP
Considere uma Sessão BGP PE NSR Capable x CE NSR non capable, em caso de switchover entre RP do PE haverá queda da sessão BGP ?
Não, o NSR transfere operação para outra RP
Para rodar BGP NSR o L3VPN deve ser configurado
verdadeiro
Como o bfd para ospf deve ser configurado no nível de interface
ip ospf bfd (apenas ativa)
bfd interval 50 min_rx 50 multiplier 3
Como o bfd para isis deve ser configurado no nível de interface
isis bfd (apenas ativa) bfd interval 50 min_rx 50 multiplier 3
como deve ser configurado um bundle em modo estatico
channel-group 12 mode on
