Download CCNP Implementing Cisco IP Routing (ROUTE v2-0).PracticeTest.300-101.2019-01-31.1e.457q.vcex

Dual stack means that devices are able to run IPv4 and IPv6 in parallel. It allows hosts to simultaneously reach IPv4 and IPv6 content, so it offers a very flexible coexistence strategy. For sessions that support IPv6, IPv6 is used on a dual stack endpoint. If both endpoints support Ipv4 only, then IPv4 is used. 
Benefits:
Native dual stack does not require any tunneling mechanisms on internal networks 
Both IPv4 and IPv6 run independent of each other 
Dual stack supports gradual migration of endpoints, networks, and applications. 
Reference: http://www.cisco.com/web/strategy/docs/gov/IPV6at_a_glance_c45-625859.pdf

Using the tunneling option, organizations build an overlay network that tunnels one protocol over the other by encapsulating IPv6 packets within IPv4 packets and IPv4 packets within IPv6 packets. The advantage of this approach is that the new protocol can work without disturbing the old protocol, thus providing connectivity between users of the new protocol.  
Tunneling has two disadvantages, as discussed in RFC 6144: 
Users of the new architecture cannot use the services of the underlying infrastructure.  
Tunneling does not enable users of the new protocol to communicate with users of the old protocol without dual-stack hosts, which negates interoperability. 
Reference: http://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/enterprise-ipv6-solution/white_paper_c11-676278.html

To clear one or more entries in the IP routing table, use the following commands in any mode:

  

Reference: http://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/unicast/5_0_3_N1_1/Cisco_n5k_layer3_ucast_cfg_rel_503_N1_1/l3_manage-routes.html

Fast switching allows higher throughput by switching a packet using a cache created by the initial packet sent to a particular destination. Destination addresses are stored in the high-speed cache to expedite forwarding. Routers offer better packet-transfer performance when fast switching is enabled. Fast switching is enabled by default on all interfaces that support fast switching. 
To display the routing table cache used to fast switch IP traffic, use the “show ip cache” EXEC command. 
Reference: http://www.cisco.com/c/en/us/td/docs/ios/12_2/switch/command/reference/fswtch_r/xrfscmd5.html#wp1038133

The TCP Window Scaling feature adds support for the Window Scaling option in RFC 1323, TCP Extensions for High Performance. A larger window size is recommended to improve TCP performance in network paths with large bandwidth-delay product characteristics that are called Long Fat Networks (LFNs). The TCP Window Scaling enhancement provides that support.  
The window scaling extension in Cisco IOS software expands the definition of the TCP window to 32 bits and then uses a scale factor to carry this 32-bit value in the 16-bit window field of the TCP header. The window size can increase to a scale factor of 14. Typical applications use a scale factor of 3 when deployed in LFNs. 
The TCP Window Scaling feature complies with RFC 1323. The larger scalable window size will allow TCP to perform better over LFNs. Use the ip tcp window-size command in global configuration mode to configure the TCP window size. In order for this to work, the remote host must also support this feature and its window size must be increased.

Access list 2 is more specific, allowing only 1.2.3.0/24, whereas access list 1 permits all 1.0.0.0/8 networks. This question also asks us to apply this distribute list only to the outbound direction of the fast Ethernet 0/0 interface, so the correct command is “distribute list 2 out FastEthernet0/0.”

With prefix lists, the ge 24 term means greater than or equal to a /24 and the le 24 means less than or equal to /24, so only a /24 is both greater than or equal to 24 and less than or equal to 24. This translates to any prefix in the 10.8.x.0/24 network, where X is any value in the 0-255 range. Only the choice of 10.8.0.0.24 matches this.

  

Reference: http://www.cisco.com/c/en/us/td/docs/ios/ipv6/command/reference/ipv6_book/ipv6_16.html

Extended Unique Identifier (EUI), as per RFC2373, allows a host to assign iteslf a unique 64-Bit IP Version 6 interface identify them EUI-64). This feature is a key benefit over IPv4 as it eliminates the need of manual configuration or DHCP as in the world of IPv4. The IPv6 EUI-64 format address is obtained through the 48-bit MAC address. The Mac address is first separated into two 24-bits, with one being OUI (Organizationally Unique Identifier) and the other being NIC specific. The 16-bit 0xFFFE is then inserted between these two 24-bits to for the 64-bit EUI address. IEEE has chosen FFFE as a reserved value which can only appear in EUI-64 generated from the EUI-48 MAC address. 
Here is an example showing how the Mac Address is used to generate EUI. 

  

Next, the seventh bit from the left, or the universal/local (U/L) bit, needs to be inverted. This bit identifies whether this interface identifier is universally or locally administered. If 0, the address is locally administered and if 1, the address is globally unique. It is worth noticing that in the OUI portion, the globally unique addresses assigned by the IEEE have always been set to 0 whereas the locally created addresses have 1 configured. Therefore, when the bit is inverted, it maintains its original scope (global unique address is still global unique and vice versa). The reason for inverting can be found in RFC4291 section 2.5.1. 

  

Once the above is done, we have a fully functional EUI-64 format address. 
Reference: https://supportforums.cisco.com/document/100566/understanding-ipv6-eui-64-bit-address

Router Advertisements (RA) are sent in response to router solicitation messages. Router solicitation messages, which have a value of 133in the Type field of the ICMP packet header, are sent by hosts at system startup so that the host can immediately autoconfigure without needing to wait for the next scheduled RA message. Given that router solicitation messages are usually sent by hosts at system startup (the host does not have a configured unicast address), the source address in router solicitation messages is usually the unspecified Ipv6 address (0:0:0:0:0:0:0:0). If the host has a configured unicast address, the unicast address of the interface sending the router solicitation message is used as the source address in the message. The destination address in router solicitation messages is the all-routers multicast address with a scope of the link. When an RA is sent in response to a router solicitation, the destination address in the RA message is the unicast address of the source of the router solicitation message.
RA messages typically include the following information:
One or more on link Ipv6 prefixes that nodes on the local link can use to automatically configure their Ipv6 addresses 
Lifetime information for each prefix included in the advertisement 
Sets of flags that indicate the type of autoconfiguration (stateless or stateful) that can be completed 
Default router information (whether the router sending the advertisement should be used as a default router and, if so, the amount of time (in seconds) the router should be used as a default router) 
Additional information for hosts, such as the hop limit and MTU a host should use in packets that it originates