Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
104 Cards in this Set
- Front
- Back
What at the three tables involved with OSPF?
|
Adjacency (neighbors), topology (LSDB), and routing table (IP routing table)
|
|
OSPF is called two tier because?
|
There is the backbone area and other areas all connect back to the backbone
|
|
What are the different roles for OSPF routers?
|
Internal, backbone, ABR, ASBR
|
|
How is cost calculated in OSPF by default?
|
Based on the interface's bandwidth.
|
|
What are the five types of OSPF packets?
|
Hello, DBD, LSU, LSR, LSAck
|
|
What are the possible OSPF neighbor states?
|
Init, two-way, exstart, exchange, loading, and full
|
|
What five fields must match in an OSPF hello packet?
|
Hello Interval, Dead Interval, Area ID, Authentication Password, and Stub Area Flag
|
|
What information is necessary for planning an OSPF implementation.
|
IP addressing, network topology, and OSPF areas.
|
|
What is the election order for the router-id?
|
Manually configured router-id, Highest IP on the loopback interfaces, and then highest configured IP on any physical interface
|
|
What are the three basic types of networks as defined by OSPF?
|
broadcast, NBMA, point-to-point
|
|
How are the DR and BDR elected?
|
Based on the interface's OPSF priority setting. The priority can either be manually configured and the router-id breaks the tie (highest wins). The default priority is one.
|
|
What are the five modes of OSPF operation for NBMA networks?
|
Nonbroadcast, Point-to-multipoint, Point-to-point, Point-to-multipoint nonbroadcast, broadcast
|
|
Which NBMA network modes are RFC-compliant
|
Non-broadcast and Point-to-mulitpoint
|
|
Which NBMA network modes are Cisco proprietary
|
broadcast, point-to-multipoint nonbroadcast, point-to-point
|
|
Whats the function of the 'always' keyword in the command 'default-information originate always' router config command
|
Generate a default route into OSPF even if the router which the command was issued on does not have its own default route in the IP routing table.
|
|
What command configures summarization on the ABR?
|
area <area-id> range <address> <mask> [advertise | not-advertise] [cost <cost>]
|
|
What are the three types of OSPF authentication?
|
Simple, null, and md5
|
|
What debug commands debugs IP OSPF authentication
|
debug ip ospf adj
|
|
What are the commands to configure OSPF simple authentication on an interface
|
ip ospf authentication-key
ip ospf authentication |
|
What are the commands to configure OSPF MD5 authentication?
|
ip ospf message-digest-key <key-id> 5
ip ospf authentication message-digest |
|
What are the two ways to assign metrics to routes being redistributed from one routing protocol to another?
|
Either using the default-metric command or by manually configuring the metric when configuring the redistribute command or by using a route-map.
|
|
True/False - Only one condition listed on the same match statement must match for the entire statement to be considered a match
|
True
|
|
True/False - A Route map has multiple match statements, each on their own line. As long as one of the lines is matched, the route-map will be matched on.
|
False - if match statements are defined on multiple lines, then all match conditions must apply. With match, separate conditions on the same line are considered logical ORs and on separate lines considered logical ANDs
|
|
How do you apply a route-map configured for policy-based routing onto an interface?
|
ip policy route-map <map-tag>
|
|
Define a distribute list
|
Allows an access list to be applied to routing updates
|
|
This command filters updates going OUT of the interface or routing protocol specified in the command, into the routing process under which it is configured.
|
distribute-list [access-list number | name] out [interface-name | routing-process]
|
|
This router configuration command assigns the access list to filter routing updates coming in through an interface. This command filters updates going into the interface specified in the command, into the routing process under which it is configured.
|
distribute-list {access-list-number | name} {route-map map-tag} in [interface-type interface-number] router configuration command
|
|
True/False - You can only use offset lists for IGP distance vector protocols like EIGRP and RIP.
|
True - you cannot use an offset-list for OSPF
|
|
What is the function of offset lists?
|
increasing incoming or outgoing metric to routes learned via EIGRP or RIP.
|
|
How is an offset-list configured?
|
offset-list {access-list-number | access-list-name} {in | out} offset {interface-type interface-number} router configuration command
|
|
Describe Cisco IP SLAs
|
Use object tracking and probing to detect network connectivity of desired objects. If the connectivity tests fail, you can configured the tracking options to perform some sort of action (failover to another route, for example)
|
|
What interface on a router would a PBR policy be applied?
|
The ingress interface on the router.
|
|
What is the different between the 'ip policy route-map' and 'ip local policy route-map' interface configuration commands?
|
The 'ip local policy route-map' command only affects packets originating on the router
|
|
What commands are used to verify and debug IP policy?
|
show ip policy
show route-map (statistics) debug ip policy |
|
What are the ranges for private ASs?
|
64512 - 65535
|
|
What are the four types of enterprise to ISP connectivity?
|
Single-homed, dual-homed, Multihomed, dual-multihomed
|
|
What are the two types of BGP peer relationships?
|
iBGP and eBGP
|
|
What are the three most common multihoming options?
|
ISP passes only a default route, each ISP passes a default route and specific provider-owned routes to the AS, each ISP passes all routes to the autonomous system
|
|
What protocol/port does BGP use?
|
TCP port 179
|
|
What does the BGP synchronization rule state?
|
That a BGP router should not use, or advertise to an external neighbor, a route learned by iBGP unless that route is local or is learned from an IGP.
|
|
What are the four BGP message types?
|
Open, Notification, Keepalive, Update
|
|
BGP attributes can be...
|
well known or optional
mandatory or discretionary transitive or non-transitive |
|
What are the three tables used by BGP?
|
the BGP table, the IP routing table, and the BGP neighbor table
|
|
List the three well-known mandatory BGP attributes
|
Origin, AS-Path, and Next-hop
|
|
List the two well-known discretionary attributes
|
Local-preference and Atomic Aggregate
|
|
What are the two optional transitive BGP attributes?
|
Aggregator and Community
|
|
What is the optional nontransitive BGP attribute?
|
Multi-exit discriminator
|
|
What is a Cisco proprietary path attribute?
|
Weight
|
|
What is the 11-step BGP route-selection process?
|
1) Prefer highest weight
2) Prefer the highest local preference 3) Prefer routes originated by the local router 4) Prefer the shortest AS-path 5) Prefer the lowest origin code 6) Prefer the lowest MED 7) Prefer the EBGP path over the IBGP path 8) Prefer the path through the closest IGP neighbor 9) Prefer the oldest route for EBGP paths 10) Prefer the path with the lowest neighbor BGP router ID 11) Prefer the route with the lowest neighbor IP address |
|
What is the purpose of BGP peer groups?
|
configure multiple BGP peers on the router that will have the same update policies,
|
|
How do you manually configure the router to use the address of a specific loopback address as the source address for BGP connections to neighbors?
|
neighbor <ip.address> update-source loopback <lo>
|
|
By default, what is the TTL value in the IP header for a BGP neighbor connection
|
TTL = 1
|
|
Does BGP support MD5 authentication between neighbors?
|
Yes
|
|
what does the ip as-path access-list acl-number {permit | deny } regexp global config command accomplish?
|
Advanced regex matching of the AS path values in BGP routing updates
|
|
Can you apply a prefix-list and/or route-map for filtering routing updates received from BGP peers?
|
yes
|
|
What type of BGP attribute is: AS-Path
|
Well-known mandatory
|
|
What type of BGP attribute is: Next-hop
|
Well-known Mandatory
|
|
What type of BGP attribute is: Origin
|
Well-known mandatory
|
|
What type of BGP attribute is: Local preference
|
Well-known discretionary
|
|
What type of BGP attribute is: Atomic Aggregate
|
Well-known discretionary
|
|
What type of BGP attribute is: Aggregator
|
Optional Transitive
|
|
What type of BGP attribute is: Community
|
Optional Transitive
|
|
What type of BGP attribute is: Multiexit discriminator
|
Optional nontransitive
|
|
If you specify the command "neighbor 10.1.1.1. ebgp-multihop', by default what is the TTL value set to without any additional parameters?
|
255
|
|
What does the command 'clear ip bgp 10.1.1.1 soft out' mean?
|
The router will send a BGP update message with the entire table for that BGP neighbor and does not reset the BGP connection. This will also contain withdrawal messages for networks that the neighbor will not see anymore due to outbound policy.
|
|
What does a > in the output of the 'show ip bgp' command mean?
|
Means the route is being offered to the IP routing table
|
|
What type of authentication does BGP support?
|
MD5
|
|
How is the established state represented in the output of the 'show ip bgp summary' command?
|
The State PfxRcd column is blank or has a number in the column indicating how many prefixes have been received from that neighbor
|
|
What is the default local preference value?
|
100
|
|
Why does it make more sense to modify the local preference value of a eBGP neighbor as the routing updates are received instead of as you readvertise the routes in iBGP?
|
Only need configured on one neighbor, and the router receiving those eBGP updates will also show the updated local preference as specified in routing policy
|
|
What is the command to assign a weigh to updates from a BGP neighbor connection?
|
neighbor x.x.x.x weight
|
|
What are the steps required to configure a GRE tunnel between two Cisco devices?
|
- Create a tunnel interface for GRE
tunnel source {ip-address | interface-type interface-number} tunnel source {ip-address | interface-type interface-number} tunnel destination {ip-address | interfae-type interface-number} - Configure the routing protocols to route through the GRE tunnel, with the network <subnet> <mask> command - Change the crypto ACL to allow GRE Traffic |
|
What does a typical global unicast IPv6 composed of?
|
A 48-bit global routing prefix, a 16-bit subnet ID, and a 64-bit interface ID (typically in EUI-64)
|
|
What prefix do IPv6 multicast addresses fall under?
|
FF00::/8
|
|
What is the IPv6 all nodes, link-local multicast?
|
FF02::1
|
|
What is the IPv6 "all routers" multicast address?
|
FF02::2
|
|
What is the IPv6 RIPng address?
|
FF02::9
|
|
What configuration command enables the forwarding of IPv6 datagrams?
|
ipv6 unicast-routing
|
|
What mechanism replaces ARP in IPv6 for mapping layer2 addresses to IPv6 addresses?
|
Neighbor Discovery?
|
|
Define SLAC
|
When IPv6 is enabled on a router, it sends RA, creates link-local addresses, and joins FF02::1 and FF02::1 multicast groups on its interfaces
|
|
T/F - EIGRP preserves all metrics between two EIGRP AS
|
True
|
|
What are the requirements to perform routing protocol redistribution?
|
The routing protocol must have at least one interface running the two routing protocols that you are redistributing between.
|
|
What are the parameters on the EIGRP redistribution command?
|
redistribute eigrp <metric bw-kbps delay-in-tens-of-microseconds reliability load mtu> <route-map>
|
|
What is the tie breaker for choosing the best E2
|
Lowest cost to reach the ASBR
|
|
What commands and options do you have when you redistributing into OSPF?
|
metric - hard-code a metric for the redistributed route
metric-type - define whether the route will be type E1 or type E2 route-map - route map preference tag - set tag for routes redistributed into OSPF |
|
What type of area are Type 7 AS External LSA generated in?
|
NSSA and NSSA no-summary areas
|
|
Filtering routes on redistribution from OSPF into EIGRP, allowing only routes permitted by ACL 1 (two methods)
|
route-map ALLOW permit 10
match ip address ACL-1 distribute-list ACL-out out ospf 1 |
|
Filtering routes on redistribution from EIGRP into OSPF allowing only routes permitted by prefix list barney (two methods)
|
route-map ALLOW permit 10
match ip address prefix-list barney distribute-list ACL-1 out eigrp 100 |
|
Configuring the route map that will set metrics components to 1000, 200, 255, 1 and 150, for routes permitted by ACL 1, and filter all other routes.
|
route-map SET permit 10
match ip add 1 set metric 1000 200 255 1 1500 |
|
Set OSPF's admin distance for all internal routes to 100 and all external routes to 180
|
distance ospf intra-area 110 inter-area 110 external 180
|
|
Set EIGRP's admin distance for routes learned from neighbors 1.1.1.1 to 190, only for subnets 10.1.0.0 - 10.1.255.255
|
access-list 5 permit 10.1.0.0 0.0.255.255
router eigrp 100 distance 190 1.1.1.1 0.0.0.0 5 |
|
single homed
|
one connection to one ISP
|
|
dual homed
|
two connections to one ISP
|
|
single multi-homed
|
one connection to two ISPs
|
|
dual multi-homed
|
two connections to two ISPs
|
|
What is the difference in the commands:
show ip bgp neighbors <x.x.x.x> received-routes & show ip bgp neighbors x.x.x.x routes |
The received-routes option will show all routes received from the specified neighbor before any inbound route filtering is applied. The 'routes' option will show inbound received routes that will be placed in the bgp table after any inbound route filtering is applied.
|
|
What is the effect of having the 'auto-summary' option enabled in the BGP configuration?
|
If a network command is specified for say, 9.0.0.0/8, the default (no auto-summary) behavior would be to add 9.0.0.0/8 only if that exact prefix/mask combo existed in the IP routing table. With auto-summary configured, any prefixes of 9.0.0.0/8 or longer will match. In that case, 9.0.0.0/8 may or may not exist but if 9.1.2.0/24 exists, it will be advertised by BGP.
|
|
What would the following command accomplish:
(config-router)# aggregate-address 128.107.0.0 255.255.224.0 summary-only |
Tells BGP to summarize any prefixes that fall within the 128.107.0.0/19 range into a single summary advertisement and advertise that summary route into BGP.
|
|
How does the 'clear ip bgp neighbor-id out' and 'clear ip bgp neighbor-id soft out' commands before the soft outbound reset?
|
The existing BGP table is re-evaluated and create a new BGP update for that neighbor. The router builds that new Update based on the existing config, so any new or changed outbound filters affect the contents of the update. The router sends the new BGP Update, and the neighboring router receives the new Update and adjusts its BGP table as a result.
|
|
Describe the impact of issuing the 'clear ip bgp <neighbor-id> soft in' command.
|
First, the command 'neighbor <neighbor-id> soft-reconfiguration inbound' command must be configured under the BGP process for that neighbor.
Then once the command is issued, the router uses it's cached received BGP pre-filtered updates for that neighbor and reevaluates that cached info against the new configuration. This allows any changes to inbound routing policy to be applied. |
|
Describe the steps that occur when the command 'clear ip bgp <neighbor-id> in' is executed?
|
The router uses the route refresh feature to request that the BGP peer re-sends its full BGP update. Then the local router can apply its new inbound route filtering policy and update the BGP table.
|
|
T/F - the 'show ip bgp neighbors <x.x.x.x> advertised-routes' shows advertised routes before outbound route filtering takes place.
|
False - the command shows routes post-outbound filtering and should represent what the BGP peer will receive in the BGP update message.
|
|
The 'show ip bgp neighbor <x.x.x.x> received-routes' command is dependent on what other configuration statement?
|
neighbor soft-reconfiguration inbound - b/c the router needs to keep a cache of the unfiltered BGP update message from the BGP peer
|
|
What are the three commands to to configure a GRE tunnel interface?
|
- Assign an IP address
- Assign a tunnel source - Assign a tunnel destination |