[PART 1] Cisco CCNA 200-125 Exam Dumps Latest version Online Exam

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DHCPv6 Technology Overview IPv6 Internet Address Assignment Overview IPv6 has been developed with Internet Address assignment dynamics in mind. Being aware that IPv6 Internet addresses are 128 bits in length and written in hexadecimals makes automation of address- assignment an important aspect within network design. These attributes make it inconvenient for a user to manually assign IPv6 addresses, as the format is not naturally intuitive to the human eye. To facilitate address assignment with little or no human intervention, several methods and technologies have been developed to automate the process of address and configuration parameter assignment to IPv6 hosts. The various IPv6 address assignment methods are as follows: 1. Manual Assignment An IPv6 address can be statically configured by a human operator. However, manual assignment is quite open to errors and operational overhead due to the 128 bit length and hexadecimal attributes of the addresses, although for router interfaces and static network elements and resources this can be an appropriate solution. 2. Stateless Address Autoconfiguration (RFC2462) Stateless Address Autoconfiguration (SLAAC) is one of the most convenient methods to assign Internet addresses to IPv6 nodes. This method does not require any human intervention at all from an IPv6 user. If one wants to use IPv6 SLAAC on an IPv6 node, it is important that this IPv6 node is connected to a network with at least one IPv6 router connected. This router is configured by the network administrator and sends out Router Advertisement announcements onto the link. These announcements can allow the on-link connected IPv6 nodes to configure themselves with IPv6 address and routing parameters, as specified in RFC2462, without further human intervention. 3. Stateful DHCPv6 The Dynamic Host Configuration Protocol for IPv6 (DHCPv6) has been standardized by the IETF through RFC3315. DHCPv6 enables DHCP servers to pass configuration parameters, such as IPv6 network addresses, to IPv6 nodes. It offers the capability of automatic allocation of reusable network addresses and additional configuration flexibility. This protocol is a stateful counterpart to "IPv6 Stateless Address Autoconfiguration" (RFC 2462), and can be used separately, or in addition to the stateless autoconfiguration to obtain configuration parameters. 4. DHCPv6-PD DHCPv6 Prefix Delegation (DHCPv6-PD) is an extension to DHCPv6, and is specified in RFC3633. Classical DHCPv6 is typically focused upon parameter assignment from a DHCPv6 server to an IPv6 host running a DHCPv6 protocol stack. A practical example would be the stateful address assignment of "2001:db8::1" from a DHCPv6 server to a DHCPv6 client. DHCPv6-PD however is aimed at assigning complete subnets and other network and interface parameters from a DHCPv6-PD server to a DHCPv6-PD client. This means that instead of a single address assignment, DHCPv6-PD will assign a set of IPv6 "subnets". An example could be the assignment of "2001:db8::/60" from a DHCPv6-PD server to a DHCPv6-PD client. This will allow the DHCPv6-PD client (often a CPE device) to segment the received address IPv6 address space, and assign it dynamically to its IPv6 enabled interfaces. 5. Stateless DHCPv6 Stateless DHCPv6 is a combination of "stateless Address Autoconfiguration" and "Dynamic Host Configuration Protocol for IPv6" and is specified by RFC3736. When using stateless-DHCPv6, a device will use Stateless Address Auto-Configuration (SLAAC) to assign one or more IPv6 addresses to an interface, while it utilizes DHCPv6 to receive "additional parameters" which may not be available through SLAAC. For example, additional parameters could include information such as DNS or NTP server addresses, and are provided in a stateless manner by DHCPv6. Using stateless DHCPv6 means that the DHCPv6 server does not need to keep track of any state of assigned IPv6 addresses, and there is no need for state refreshment as result. On network media supporting a large number of hosts associated to a single DHCPv6 server, this could mean a significant reduction in DHCPv6 messages due to the reduced need for address state refreshments. From Cisco IOS 12.4(15)T onwards the client can also receive timing information, in addition to the "additional parameters" through DHCPv6. This timing information provides an indication to a host when it should refresh its DHCPv6 configuration data. This behavior (RFC4242) is particularly useful in unstable environments where changes are likely to occur.

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http://www.cisco.com/c/en/us/support/docs/ip/hot-standby-router-protocol-hsrp/9234-hsrpguidetoc.html#multihsrp Using HSRP, a set of routers works in concert to present the illusion of a single virtual router to the hosts on the LAN. This set is known as an HSRP group or a standby group. A single router elected from the group is responsible for forwarding the packets that hosts send to the virtual router. This router is known as the Active router. Another router is elected as the Standby router. In the event that the Active router fails, the Standby assumes the packet-forwarding duties of the Active router. Although an arbitrary number of routers may run HSRP, only the Active router forwards the packets sent to the virtual router. To minimize network traffic, only the Active and Standby routers send periodic HSRP messages once the protocol has completed the election process. If the Active router fails, the Standby router takes over as the Active router. If the Standby router fails or becomes the Active router, then another router is elected as the Standby router. On a particular LAN, multiple hot standby groups may coexist and overlap. Each standby group emulates a single virtual router. The individual routers may participate in multiple groups. In this case, the router maintains separate state and timers for each group. Each standby group has a single, well-known MAC address, as well as an IP address.

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Output from real device Router2901#sh int g0/0 GigabitEthernet0/0 is up, line protocol is up Hardware is CN Gigabit Ethernet, address is c471.fe99.9999 (bia c471.fe99.9999) Description: Lan Internet address is 10.1.1.1/25 MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Full Duplex, 1Gbps, media type is RJ45 output flow-control is unsupported, input flow-control is unsupported ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:00:00, output 00:00:00, output hang never Last clearing of “show interface” counters never Input queue: 0/75/61/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 39000 bits/sec, 30 packets/sec 5 minute output rate 73000 bits/sec, 37 packets/sec 41068530 packets input, 3905407112 bytes, 0 no buffer Received 8678853 broadcasts (0 IP multicasts) 0 runts, 0 giants, 45 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 79853 multicast, 0 pause input 39267208 packets output, 2262399504 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 79926 unknown protocol drops 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier, 0 pause output 0 output buffer failures, 0 output buffers swapped out Router2901# Router2901 ip int g0/0 GigabitEthernet0/0 is up, line protocol is up Internet address is 10.1.1.1/25 Broadcast address is 255.255.255.255 Address determined by non-volatile memory MTU is 1500 bytes Helper address is not set Directed broadcast forwarding is disabled Secondary address 192.168.1.7/24 Multicast reserved groups joined: 224.0.0.10 Outgoing access list is not set Inbound access list is not set Proxy ARP is enabled Local Proxy ARP is disabled Security level is default Split horizon is enabled ICMP redirects are always sent ICMP unreachables are always sent ICMP mask replies are never sent IP fast switching is enabled IP fast switching on the same interface is disabled IP Flow switching is disabled IP CEF switching is enabled IP CEF switching turbo vector IP multicast fast switching is enabled IP multicast distributed fast switching is disabled IP route-cache flags are Fast, CEF Router Discovery is disabled IP output packet accounting is disabled IP access violation accounting is disabled TCP/IP header compression is disabled RTP/IP header compression is disabled Policy routing is disabled Network address translation is enabled, interface in domain inside BGP Policy Mapping is disabled Input features: Common Flow Table, Stateful Inspection, Virtual Fragment Reassembly, Virtual Fragment Reassembly After IPSec Decryption, CAR, MCI Check Output features: NAT Inside, Common Flow Table, Stateful Inspection, NAT ALG proxy, CAR Post encapsulation features: CAR IPv4 WCCP Redirect outbound is disabled IPv4 WCCP Redirect inbound is disabled IPv4 WCCP Redirect exclude is disabled Router2901#

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The 10.0.0.0/22 subnet mask will include the 10.0.0.0, 10.0.1.0, 10.0.2.0, and 10.0.3.0 networks, and only those four networks.

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Output from real device Router2901#sh int g0/0 GigabitEthernet0/0 is up, line protocol is up Hardware is CN Gigabit Ethernet, address is c471.fe99.9999 (bia c471.fe99.9999) Description: Lan Internet address is 10.1.1.1/25 MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Full Duplex, 1Gbps, media type is RJ45 output flow-control is unsupported, input flow-control is unsupported ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:00:00, output 00:00:00, output hang never Last clearing of “show interface” counters never Input queue: 0/75/61/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 39000 bits/sec, 30 packets/sec 5 minute output rate 73000 bits/sec, 37 packets/sec 41068530 packets input, 3905407112 bytes, 0 no buffer Received 8678853 broadcasts (0 IP multicasts) 0 runts, 0 giants, 45 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 79853 multicast, 0 pause input 39267208 packets output, 2262399504 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 79926 unknown protocol drops 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier, 0 pause output 0 output buffer failures, 0 output buffers swapped out Router2901# Router2901 ip int g0/0 GigabitEthernet0/0 is up, line protocol is up Internet address is 10.1.1.1/25 Broadcast address is 255.255.255.255 Address determined by non-volatile memory MTU is 1500 bytes Helper address is not set Directed broadcast forwarding is disabled Secondary address 192.168.1.7/24 Multicast reserved groups joined: 224.0.0.10 Outgoing access list is not set Inbound access list is not set Proxy ARP is enabled Local Proxy ARP is disabled Security level is default Split horizon is enabled ICMP redirects are always sent ICMP unreachables are always sent ICMP mask replies are never sent IP fast switching is enabled IP fast switching on the same interface is disabled IP Flow switching is disabled IP CEF switching is enabled IP CEF switching turbo vector IP multicast fast switching is enabled IP multicast distributed fast switching is disabled IP route-cache flags are Fast, CEF Router Discovery is disabled IP output packet accounting is disabled IP access violation accounting is disabled TCP/IP header compression is disabled RTP/IP header compression is disabled Policy routing is disabled Network address translation is enabled, interface in domain inside BGP Policy Mapping is disabled Input features: Common Flow Table, Stateful Inspection, Virtual Fragment Reassembly, Virtual Fragment Reassembly After IPSec Decryption, CAR, MCI Check Output features: NAT Inside, Common Flow Table, Stateful Inspection, NAT ALG proxy, CAR Post encapsulation features: CAR IPv4 WCCP Redirect outbound is disabled IPv4 WCCP Redirect inbound is disabled IPv4 WCCP Redirect exclude is disabled Router2901#

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http://www.cisco.com/c/dam/en_us/about/ciscoitatwork/downloads/ciscoitatwork/pdf/cisco_it_case_study_multicast.pdf Cisco IOS IP Multicast in the Cisco Network “IP Multicast as defined in RFC1112, the standard for IP Multicast across networks and the Internet, supports one-to-many content needs by delivering application-source traffic to multiple users without burdening the source or the network, using a minimum amount of network bandwidth. At the point where paths diverge, Cisco routers replace IP Multicast packets in the network, resulting in the most efficient delivery of data to multiple receivers.” Even low-bandwidth applications can benefit fro IP Multicast when there are thousands of receivers. High-bandwidth applications, such as MPEG video, may need a large portion of the available network bandwidth for a single stream. In these applications, IP Multicast is the only way to efficiently send the same content to more than one receiver simultaneously, because it makes sure that only one copy of the data stream is sent across any one network link. It relies on each router in the stream to intelligently copy the data stream whenever it needs to deliver it to multiple receivers.

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from W.Odom Official Cert Guide for ICND1 v3 Telcos offer a wide variety of speeds for leased lines. However, you cannot pick the exact speed you want; instead, you must pick from a long list of predefined speeds. Slower-speed links run at multiples of 64 kbps (kilobits per second), while faster links run at multiples of about 1.5 Mbps (megabits per second). Leased lines have many benefits that have led to their relatively long life in the WAN mar- ketplace. These lines are simple for the customer, are widely available, are of high quality, and are private. However, they do have some negatives as well compared to newer WAN technologies, including a higher cost and typically longer lead times to get the service installed.

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0 emergencies System is unusable 1 alerts Immediate action is needed 2 critical Critical conditions exist 3 errors Error conditions exist 4 warnings Warning conditions exist 5 notification Normal, but significant, conditions exist 6 informational Informational messages 7 debugging Debugging messages

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http://www.ieee802.org/3/ CSMA/CD – It uses a carrier sensing scheme in which a transmitting station detects collisions by sensing transmissions from other stations while transmitting a frame. When this collision condition is detected, the station stops transmitting that frame.

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http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_pi/configuration/xe-16/iri-xe-16-book/iri-recursive-static-route-xe.html

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https://en.wikipedia.org/wiki/Dynamic_Trunking_Protocol.

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http://flylib.com/books/2/686/1/html/2/images/1587051990/graphics/13fig01.gif

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Explanation from http://www.9tut.com/trunking-questions Maybe this question wanted to ask “if the other end is configured with trunk/access/desirable mode” then which mode is compatible so that the link can work. In that case both “dynamic auto” and “dynamic desirable” mode are correct. The difference between these two modes is “dynamic auto” is passively waiting for the other end to request to form a trunk while “dynamic desirable” will actively attempt to negotiate to convert the link into a trunk.

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Router(config)# logging trap level – Specifies the kind of messages, by severity level, to be sent to the syslog server. The default is informational (6) and lower ( 0 ­ 6). The possible values for level are as follows: Emergency: 0 Alert: 1 Critical: 2 Error: 3 Warning: 4 Notice: 5 Informational: 6 Debug: 7