Ch 3 - IPv6 Review and RIPng Flashcards
Which of the following is the shortest valid abbreviation for FE80:0000:0000:0000:0 010:0000:0000:0123?
a. FE80::10::123
b. FE8::1::123
c. FE80:0:0:0:10::123
d. FE80::10:0:0:123
D. Inside a quartet, any leading 0s can be omitted, and one sequence of one or more quartets of all 0s can be replaced with “::”. The correct answer replaces the longer three-quartet sequence of 0s with ::.
An ISP has assigned prefix 3000:1234:5678::/48 to Company1. Which of the following terms would typically be used to describe this type of public IPv6 prefix?
a. Subnet prefix
b. ISP prefix
c. Global routing prefix
d. Registry prefix
C. The name of the prefix generally represents the group to which the prefix is given, with the exception of the term global routing. IANA assigns a prefix to a registry (registry prefix). The registry can assign a subset of that range as a prefix to an ISP (ISP prefix). That ISP then subdivides that range of addresses into prefixes and assigns a prefix to one of its customers (site prefix, also called global routing prefix). The enterprise network engineers then further subdivide the range, often with prefix length 64, into subnet prefixes.
Which of the following answers list either a protocol or function that can be used by a host to dynamically learn its own IPv6 address? (Choose two.)
a. Stateful DHCP
b. Stateless DHCP
c. Stateless autoconfiguration
d. Neighbor Discovery Protocol
A and C. IPv6 supports stateful DHCP, which works similarly to IPv4’s DHCP to dynamically assign the entire IP address. Stateless autoconfiguration also allows for the assignment by finding the prefix from some nearby router and calculating the Interface ID using the EUI-64 format. Stateless DHCP simply supplies the DNS server IP addresses, and NDP supplies Layer 2 mapping information.
Which of the following is helpful to allow an IPv6 host to learn the IP address of a default gateway on its subnet?
a. Stateful DHCP
b. Stateless RS
c. Stateless autoconfiguration
d. Neighbor Discovery Protocol
D. Stateless auto-configuration only helps a host learn and form its own IP address, but it does not help the host learn a default gateway. Stateless RS is not a valid term or feature. Neighbor Discovery Protocol (NDP) is used for several purposes, including the same purpose as ARP in IPv4, plus to learn configuration parameters such as a default gateway IP address.
Which of the following answers lists a multicast IPv6 address?
a. 2000::1:1234:5678:9ABC
b. FD80::1:1234:5678:9ABC
c. FE80::1:1234:5678:9ABC
d. FF80::1:1234:5678:9ABC
D. Global unicast addresses begin with 2000::/3, meaning that the first 3 bits match the value in hex 2000. Similarly, unique local addresses match FD00::/8, and link-local addresses match FE80::/10 (values that begin with FE8, FE9, FEA, and FEB hex). Multicast IPv6 addresses begin FF00::/8, meaning that the first two hex digits are F.
Router R1 has two LAN interfaces and three serial interfaces enabled for IPv6. All the interfaces use link-local addresses automatically generated by the router. Which of the following could be the link-local address of R1’s interface S0/0?
a. FEA0::200:FF:FE11:0
b. FE80::200:FF:FE11:1111
c. FE80::0213:19FF:FE7B:0:1
d. FEB0::211:11FF:FE11:1111
B. When created automatically, link-local addresses begin FE80::/64, because after the prefix of FE80::/10, the device builds the next 54 bits as binary 0s. Statically assigned link-local addresses simply need to conform to the FE80::/10 prefix. As a result, only two answers are candidates with a beginning quartet of FE80. Of these, only one has only hex 0s in the second, third, and fourth quartets, making answer B the only valid answer.
Router R1 has the following configuration. Assuming that R1’s F0/0 interface has a MAC address of 0200.0011.1111, what IPv6 addresses will R1 list for interface F0/0 in the output of the show ipv6 interface brief command? (Choose two.)
interface f0/0 ipv6 address 2345:0:0:8::1/64
a. 2345:0:0:8::1
b. 2345:0:0:8:0:FF:FE11:1111
c. FE80::FF:FE11:1111
d. FE80:0:0:8::1
A and C. The ipv6 address command does not list an eui-64 parameter, so R1 does not form its global unicast address using the EUI-64 format. However, it does form its link-local address using EUI-64. The show ipv6 interface brief command lists both the global unicast and link-local addresses in its output.
Router R1 lists the following output from a show command. Which of the following is true about R1?
R1# show ipv6 interface f0/0 FastEthernet0/0 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::213:19FF:FE12:3456
No Virtual link-local address(es):
Global unicast address(es):
2000::4:213:19FF:FE12:3456, subnet is 2000:0:0:4::/64 [EUI]
Joined group address(es):
FF02::1
FF02::2
FF02::1:FF12:3456
a. R1’s solicited node multicast address is FF02::1:FF12:3456.
b. R1’s 2000::4:213:19FF:FE12:3456 address is a global unicast with all 128 bits
statically configured.
c. Address FF02::2 is R1’s solicited node multicast.
d. R1’s solicited node multicast, not listed in this output, would be FF02::213:19FF:FE12:3456.
A. The group addresses listed in the output are the all IPv6 hosts address (FF02::1), the all IPv6 routers address (FF02::2), and the solicited node address that is based on R1’s global unicast address (FF02::1:FF12:3456). Also, R1’s global unicast address is listed correctly in answer B, but the “[EUI]” notation implies that R1 derived the interface ID portion using EUI-64 conventions.
Which of the following features work the same in both RIPv2 and RIPng? (Choose three.)
a. Distance Vector Logic
b. Uses UDP
c. Uses RIP-specific authentication
d. Maximum useful metric of 15
e. Automatic route summarization
A, B, and D. RIPv2 and RIPng both use UDP, both use distance-vector logic, and both use the same metric, with the same maximum (15) and same metric that means infinity (16). RIPng does not perform automatic route summarization because IPv6 has no concept of a classful network. RIPng also uses the built-in IPv6 authentication mechanisms rather than a RIP-specific authentication such as RIPv2.
Router R1 currently has no configuration related to IPv6 or IPv4. The following configuration exists in a planning document, intended to be used to copy/paste into Router R1 to enable RIPng and IPv6 on interfaces Fa0/0 and S0/0/0. No other related configuration exists. Which of the following is true about RIPng on R1 after this configuration has been pasted into R1?
ipv6 unicast-routing
interface fa0/0
ipv6 rip one enable
ipv6 address 2000::1/64
interface s0/0/0
ipv6 address 2001::/64 eui-64
ipv6 rip one enable
a. RIPng will be enabled on no interfaces.
b. RIPng will be enabled on one interface.
c. RIPng will be enabled on two interfaces.
d. RIPng will advertise about prefixes connected to S0/0/0 and Fa0/0, but only send Updates on one interface.
B. The fact that the configuration will be copied/pasted into a router means that the order of the commands matters. In this case, the fact that the ipv6 rip one enable command precedes the ipv6 address command on interface f0/0 means that Cisco IOS will reject the first of these commands, therefore not enabling RIPng on F0/0. The correct order listed under S0/0/0 means that RIPng will be enabled on S0/0/0. As a result, RIPng on R1 will advertise about S0/0/0’s connected IPv6 prefixes, and send Updates on S0/0/0, but will do nothing related for F0/0.
T/F: In IPv6 per packet overhead is reduced because routers do not need to recalculate header checksums.
True.
T/F: IPv6 headers have a field that easily identifies packets that are sent over the same TCP/UDP connection.
True. The Flow Label field IDs them.
T/F: Like IPv4, IPv6 supports unicast, multicast and broadcast.
False. IPv6 does not support broadcast.
T/F: IANA assigns addresses to ICANN who in turn hands them out to the RIRs who give them to ISPs.
False.The process of global address assignment of IPv6 address space is managed by IANA. IANA is is a function ofICANN, a nonprofit privateAmericancorporation that oversees globalIP addressallocation,autonomous systemnumber allocation,root zonemanagement in theDomain Name System(DNS),media types, and otherInternet Protocol-related symbols andInternet numbers. IANA assigns one or more IPv6 address ranges to each RIR who in turn assign prefixes to the ISPs.
How many RIRs are there? Name them.
- ARIN, AfriNIC, APNIC, LACNIC, RIPE-NCC
How many hex digits are there in an IPv6 address?
- Each hex digit is 4 bits for a total of 128 bits for an IPv6 address.
What are the two rules for shortening an IPv6 address?
- Omit leading zeroes in any given quartet of hex digits 2. Represent one or more consecutive quartets of all hex 0s with ::, but only once.
If a quartet is 4 hex digits, how many quartets in an IPv6 address?
8
Which of these are valid shortenings of this IPv6 address: FE00:0000:0000:0001:0000:0000:0000:0056. A. FE00::1:0:0:0:56 B. FE00:0:0:1:::56 C. Neither D. Both
D. Both are valid.
T/F: IPv6 is a classful style of addressing.
False. Prefixes are very similar to VLSM and CIDR
What is the prefix of: 2000:1234:5678:9ABC:1111:1234:5678:9ABC/64 (the network address)
2000:1234:5678:9ABC::/64
What is the prefix of: 2000:1234:5678:9ABC:1111:1234:5678:9ABC/56 (the network address)
2000:1234:5678:9A00::/56 The last 8 bits are zero because they are host bits and not part of the prefix. Host bits are always written as zero in a network address.
T/F: When writing an IPv6 prefix, any bits after the prefix length number of bits are zero.
True.
T/F: When writing an IPv6 prefix, if the prefix length is not on a quartet boundary, write down the value for the entire quartet.
True.
If you are assigned the routing prefix 2019:DEAD:BEEF/48 by your ISP and you want to use EUI-64 for address assignment, how large will your network prefix be? (The assigned routing prefix plus your subnet ID.) i.e. How many hex digits and how many subnets is that?
The combined network prefix is /64, 48 bits(12 hex digits) from the ISP assigned routing prefix, 16 bits (4 hex digits) for your subnets and 64 bits for hosts, which is a LOT of hosts per subnet.
T/F: A prefix cannot be abbreviated with the same rules as a full IPv6 address.
False. The same two rules can be applied.
Is 31AF::1234/3 a valid global unicast address?
Yes. The prefix reserved for global unicast addresses 2000::/3. This includes all IPv6 address where the first 3 bits are binary 001, or in hex the fist digit is either 2 or 3. Decimal 3 = 0011 in binary. The full address is: 31af:0000:0000:0000:0000:0000:0000:1234
What does 2340:1140::/26 mean?
This represents all addresses whose first 26 bits match the written hex number. Interestingly, the number of bits in the prefix does not break on a hex digit boundary. The third hex quartet is split down the middle. This is legal. Writing the last hex digit as zero is the correct version of the prefix notation. Omitting the trailing zero in the second quartet is incorrect, like: 2340:114::/26 (see page 82 in the text). This makes sense on a binary level if you break it down. Hex 4 = 0100 in binary, the 01 fall into the prefix bits, and the host bits are always 00, so 1140 is right. Hex 4 = 0100.
What is the prefix of 2340:1120::1/26 ?
2340:1100::/26. Look at the digits in binary, it makes sense. Hex 2 = 0010 in binary, the 0s fall into the prefix bits, and the host bits are always 00, so 1100 is right. Hex 0 = 0000
What is the prefix of 2340:1150::1/26 ?
2340:1140::/26 Look at the digits in binary, it makes sense. Hex 5 = 0101 in binary, 01 falls into the prefix side and the two host bits are 00, so 1140 is right. Hex 4 = 0100
What is the prefix of 2340:11FF::1/26?
2340:11c0::/26. Look at the digits in binary. It makes sense. Hex F = 1111 in binary, there are two 1s on the prefix side and two 0s on the host side. Hex C=1100.
In IPv6, Stateful DHCP supplies which of the following: A. IPv6 address B. DNS server address(s) C. Prefix length D. Default router
Stateful DHCP servers supply A, B and C. Clients use NDP to find their default router.
What is the IPv6 reserved range for multicast?
FF00::/8
What is the IPv6 multicast address for an unknown DHCP server?
FF02::1:2 or in long hand: FF02:0000:0000:0000:0000:0000:0001:0002
Which of the following can be learned by a host using SLAAC? A. Prefix B. Prefix Length C. Host ID D. Default router E. DNS server address(s)
SLAAC can provide all of these. SLAAC used NDP RS and RA msgs to learn prefix, prefix length and default router from a router on the local segment. EUI-64 provides the Interface ID. SLAAC relies on stateless DHCP to learn the IPv6 DNS server addresses.
Company A is assigned the global routing prefix 2340:1111:AAAA::/48 from it’s local ISP. What are the first four subnets (use 1,2,3,4) if a 16-bit subnet field is used with this site prefix?
2340:1111:AAAA:0001/64, 2340:1111:AAAA:0002/64, 2340:1111:AAAA:0003/64, 2340:1111:AAAA:0004/64.
Company A is assigned the global routing prefix 2340:1111:AAAA::/48 from it’s local ISP. You have decided that you need a lot of subnets. What are the first four subnets (use 1,2,3,4) if a 112-bit prefix is used?
2340:1111:AAAA::0001:0000/112, 2340:1111:AAAA::0002:0000/112, 2340:1111:AAAA::0003:0000/112, 2340:1111:AAAA::0004:0000/112,
T/F: in IPv6 each VLAN needs it’s own subnet.
True.
T/F: In IPv6 each serial link needs it’s own subnet.
True.
Which of the following global unicast address assignment methods is the default router learned from NDP? A. Stateful DHCP B. SLAAC C. Static assignment D. Static assignment with EUI-64
Actually, all of them. NDP RS and RA messages always supply the default router information to the hosts in IPv6.
Which of the following global unicast address assignment methods uses Stateless DHCP to provide the DNS server address(s)? A. Stateful DHCP B. SLAAC C. Static config D. Static config with EUI-64
B, C and D. All 3 of these methods rely on stateless DHCP to provide the DNS server address(s).
Which of the following global unicast address assignment methods is the prefix and length learned from the router via NDP? A. Stateful DHCP B. SLAAC C. Static assignment D. Static assignment with EUI-64
SLAAC. Stateful DHCP server provide prefix and length and Static Config with and w/out EUI-64 get it from the local config.
T/F: The IPV6 Interface ID is derived from the MAC address if you are using SLAAC for global unicast address assignment.
True. SLAAC relies on the EUI-64 method.
T/F ICMPv6 can be used to learn prefix and length on an IPv6 segment.
True. Hosts on a link can ask routers to give 2 pieces of info. 1. All routers willing to act as default gateway and 2. All know IPv6 prefixes on that link. This process uses RS and RA messages, Router Solicitation and Router Advertisements. For this to work routers need to be configured for IPv6, with and IPv6 address on that segment and configured to route IPv6.
What address do clients/hosts send RS msgs to?
FF02:2 This is the All IPv6 routers multicast address.
When routers are replying with an RA msg to a host’s RS request, what address do they reply to?
FF02::1 This is the all IPv6 hosts address on a link. This reply never leaves the local link, routers will not forward it. The RA contains prefix/length and default routers on the link. Note: IPv6 allows multiple prefixes and routers to be included in the RA msg.
T/F: EUI-64 calculates a 64-bit Interface ID using the BIA.
True.
T/F: EUI-64 takes a 48-bit MAC, inserts four bytes in the middle to make a 64-bit Interface ID.
False. EUI-64 takes a 48-bit MAC, inserts two bytes in the middle and flips the 7th bit of the first byte to make a 64-bit Interface ID. Four hex digits = 2 bytes.
What does EUI-64 insert into the MAC to form an Interface ID?
FFFE. EUI-64 also flips the 7th bit of the first byte. (reading left to right)
What is the BIA of this host? 1234:DEAD:BEEF:1:234:56FF:FE78:9ABC/64
00.34.56.78.9A.BC
What does EUI stand for?
Extended Unique Identifier
T/F: Stateless DHCP assigns IP addresses to clients but does not track any state information about the leases.
False. Stateless DHCP does not assign IP addresses to clients, it only provides the DNS server IP address(s).
What are the two ways to configure a static IPv6 address?
- Config the entire 128-bit address 2. Config a 64-bit prefix and use EUI-64.
What is the command to configure an IPv6 default router at the CLI?
There isn’t one. NDP always provides this via RS/RA msgs!
T/F: Anycast is a feature of IPv6 and is not found in IPv4, but in practice IPv4 can be similarly implemented.
True. Anycast used the exact same global unicast Interface ID for two servers with exactly the same function.
IPv4 can have similar functionality by leveraging geo-located DNS and a similar config with the same IPs on two servers having same functionality.
How does IPv6 propagate L3 broadcasts?
It does not! There are no L3 broadcasts in IPv6. It does however make extensive use of multicast.
T/F: IPv6 allows multiple addresses to be configured on an interface without the use of the ‘secondary’ command.
True.
What are the 3 types of IPv6 unicast addresses?
Unique local, Link Local and Global Unicast. Unique Local addressing is equivalent to RFC1918, which is SOOO last century… no, last millenium! RFC 4193 is the new RFC1918. Link Local addresses send/receive on the local link only and routers will not forward these packets. Global unicast are the standard 128 bit 2000::/3 addresses.
What is the prefix for Unique Local addresses in IPv6?
FC00::/7 You could use these addresses instead of registering a public prefix from an ISP. Note: Locally assigned Unique Local addresses have FD as the first two hex digits. To form this address a 40-bit prefix is pseudo-randomly chosen and prepended with FD. (49 bit prefix) This allows for a 16 bit subnet field and a 64-bit host field that is eligible for EUI-64. You could assign all the hosts statically if you wanted to.
What is the prefix for an IPv6 Link Local address?
FE80::/10 This states that the first 10 bits are 1111 1110 10. Technically these addresses could begin with FE8, FE9, FEA, or FEB due to the 3rd hex digit’s first two bits being 01 and the last two bits could be 00, 01, 10, or 11. In practice you will always see FE80 because the auto-config process sets bits 11-64 to all 0s. Auto-config uses EUI-64 to complete the Link Local address.
T/F: Hosts calculate their Link Local address before they send anything.
True.
T/F: IPv6 link local addresses are used by NDP as the source address for RS//RA msgs.
True.
T/F: IPv6 Link Local addresses have a single directly connected link as their scope.
True.
What is the IPv6 address ::/128? When is it used?
Unknown address. This is used as a source address when a host has no suitable IPv6 address to use.
What is the IPv6 address ::1/128? What is it used for?
Loopback address. All 0s except for last digit is 1. Equivalent to 127.0.0.1 in IPv4. This is used for testing-packets sent to this will be looped up the TCP stack for software testing.
T/F: Global unicast addresses can begin with either 2 or 3 as the first hex digit. Why or why not?
True. 2000::/3 states that the first 3 digits are 001. The first four binary digits could be 0010 or 0011, in hex that is 2 or 3. IPv6 public unicast addresses begin with this.
What is the multicast prefix for DHCP relay agents?
FF02::1:2
What is the multicast prefix for all IPv6 hosts on a link?
FF02::1
What does DAD stand for?
Duplicate Address Detection.
T/F: Hosts use NDP NS and NA messages to confirm that they do not have a duplicate IPv6 address when they first lean an IP address and before an interface is brought up.
True. They also use DAD after being down for any reason and when they first begin working.
What replaces ARP in IPv6?
NDP. Neighbor Discovery Protocol
T/F: IPv6 hosts maintain a ‘neighbor table’ with data link addresses to IPv6 mappings.
True. e.g. PC1 wants to send a frame to R1. If there is no L3-L2 entry in the neighbor table NDP will send a NS message asking for the data-link address of R1. The destination address of the NS message is the Solicited Node Multicast address of R1. The SA is PC1’s IPv6 address. R1 will reply with a NA msg containing it’s MAC address. The NA destination is PC1’s IPv6 address and the source address is R1’s IPv6 address. This replaces ARP.
What does a Solicited Node Multicast address begin with?
FF02::1:FF00:0/104.
How are the last 24 bits of the Solicited Node Multicast address formed?
The last 6 hex digits are the last 24 bits of the address to which the message is being sent.
T/F: Messages sent to the Solicited Node Multicast address are sent to the intended host plus a few more.
True. This is by design.
T/F: All hosts listen for messages sent to their own Solicited Node Multicast address.
True.
What is the Solicited Node Multicast address of this IPv6 unicast address? 2340:1111:AAAA:1:213:19FF:FE7B:5004
FF02::1:FF7B:5004 This is formed by combining FF02:::1:FF00:0/104 with 7B:5004. The long version of the Solicited Node Multicast address makes this more obvious: FF02:0000:0000:0000:0000:0001:FF00:0000 - The last six hex digits get added on to the end.
What message types are used to do a MAC to IP mapping?
Inverse Neighbor Discovery uses InverseNA and Inverse NS messages. Inverse Neighbor Solicitation messages list the known link-layer address, a DLCI for instance, and ask for the IPv6 address.
What is the IPv6 destination address of an Inverse Neighbor Solicitation message?
FF02::1 - All IPv6 nodes on the local link.
What does the global config command “ipv6 flow set” do?
Used for configuring flow-label marking in 1280 byte or larger packets sent from the router.
What is the command to use SLAAC on an interface?
R1(config-if)# ipv6 address autoconfig
What is the command to use stateful DHCP on a router interface?
R1(config-if)# ipv6 address dhcp
What is the command to configure a static IP using a prefix of 2001:DEAD:BEEF:0001::/64 and EUI-64?
R1(config-if)# ipv6 address 2001:DEAD:BEEF:0001::/64 eui-64
What is the command to configure a 128-bit static IP using a prefix of 2001:3:2:1::1/64
R1(config-if)# ipv6 address 2001:3:2:1::1/64
What is the effect of issuing the “ipv6 enable” command on an interface?
This enables IPv6 on an interface and results in only a Link Local address being created.
What does this command do? R1(config-if)# ipv6 address FEAD::240:D0FF:FE48:4672 link-local
This creates a static link-local address. It will override the auto-generated one. Note: Static link-local addresses must conform to the FE80::/10 prefix.
T/F: If you statically configure a global unicast address on an interface, a link-local address will automatically be created.
True. As soon as you assign an IP to an interface, IPv6 is enabled on that interface and a link-local address is auto-generated.
T/F: Interfaces on a router can be configured with an IPv6 address without the global command “ipv6 unicast-routing”?
True. But, the router will act as a host and will not route packets!
T/F: If an interface does not have a BIA then Cisco will use the MAC address from the highest numbered LAN interface.
False. The lowest numbered LAN interface’s MAC is used.
What are the 3 multicast groups all IPv6 routers join? Give the multicast addresses and assume the Router has an interface with a BIA of 0002:7E12:3456
- FF02::1 - all IPv6 hosts on link
- FF02::2 - all IPv6 routers on link
- FF02::1:FF12:3456 - router’s own solicited node multicast address.
What is the command to display the table that maps IPv6 addresses to data link addresses?
R1# show ipv6 neighbors. This will display the neighbor table and contains the IPv6 addresses along with MACs, what interface they are reachable on, and a state field showing REACH if they are reachable.
T/F: RIPng was named after Star Trek Next Generation.
True. Fun fact!
What IPv6 multicast address replaces 224.0.0.9 from IPv4? What protocol is this talking to?
FF02::9 - This is the multicast address for all RIPng routers.
Does RIPng use TCP or UDP for messaging between routers? What port?
UDP 521. RIPv2 uses 520
What is the AD of RIPng?
120, same as RIPv2.
Which of the following is the same in RIPng as it was in RIPv2? A. Uses Split Horizon B. Uses Poison reverse C. Updates are sent every 30 seconds D. Slow convergence time E. Network router sub-command
A, B, C, D are the same. The network command has been deprecated.
T/F: Multiple RIP processes may run on a router at one time.
True. The differentiator is the “name”.
How do you enable RIPng on multiple interfaces?
You need to enable RIPng on each interface. R1(config-if)# ipv6 rip CCNP_RIP enable CCNP_RIP is the name of the RIP process.
In what sequence do these commands need to be issued? A. R1(config-if)# ipv6 rip CCNP_RIP enable B. R1(config)# ipv6 router rip CCNP_RIP C. R1(config-if)# ipv6 address 2019:BAD:BAD:BAD::200:521/64 D. R1(config)# ipv6 unicast-routing
D, B, C, A. There are some dependencies. B is dependent on A and you will get an error if you issue B before A. D is dependent on C, but C will be automatically created by D if need be. If you fat-finger the “name” on D you will spawn a new RIPng process with that name and get no error/warning message.
What command will show the RIPng timers?
Sh ipv6 rip
How long does a route take to expire in a RIPng table once it is no longer advertised?
180 seconds. “Clear ipv6 rip” will flush the RIP table and force all the routes to be relearned… but don’t do this in production environments.
What does this command do? R1(config-if)# ipv6 rip CCNP_RIP default-information only
This will cause RIPng to only advertise default routes. “default-information originate” will advertise the default routes and announce dynamic routes.
R1 has a directly connected subnet, subnet A, and a serial link. R2 is connected to R1 via the serial link. What is the metric of subnet A in R2’s routing table?
- RIP routers consider themselves to be one hop so they advertise their directly connected routes with a metric of 1. R2 adds one to this for a metric of 2 hops.
