Which two of these are used in the selection of a root bridge in a network utilizing Spanning Tree ProtocolIEEE 802.1 D？（）

单项选择题SpanningTreeProtocolIEEE802.1sdefinestheabilitytodeploywhichofthese？（）

A.one global STP instance for all VLANs
B.one STP instance for each VLAN
C.one STP instance per set of VLANs
D.one STP instance per set of bridges

单项选择题TworoutersconfiguredtorunBGPhavebeenconnectedtoafirewall，oneontheinsideinterfaceandone ontheoutsideinterface.BGPhasbeenconfiguredsothetworoutersshouldpeer，includingthecorrectBGPsessionendpointaddressesandthecorrectBGPsessionhop-countlimitEBGPmultihop.WhatisagoodfirsttesttoseeifBGPwillworkacrossthefirewall？（）

A.Attempt to TELNET from the router connected to the inside of the firewall to the router connected to theoutside of the firewall. If telnet works， BGP will work， since telnet and BGP both use TCP to transportdata.
B.Ping from the router connected to the inside interface of the firewall to the router connected to theoutside interface of the firewall. If you can ping between them， BGP should work， since BGP uses IP totransport packets.
C.There is no way to make BGP work across a firewall without special configuration， so there is no simpletest that will show you if BGP will work or not， other than trying to start the peering session.
D.There is no way to make BGP work across a firewall.

多项选择题Choosetwocommandsthatarerequiredtoenablemulticastonarouter，whenitisknownthatthereceiversuseaspecificfunctionalityofIGMPv3.（）

A.ip pim rp-address
B.ip pim ssm
C.ip pim sparse-mode
D.ip pim passive

单项选择题WhatisalsocalledType0authenticationinOSPFonCiscoRouters？（）

A.MD5
B.There is no Type 0 authentication
C.SHA1
D.Null

单项选择题WhichprotocolandporthavebeenassignedbyIANAforRADIUSauthentication？（）

A.UDP/1812
B.UDP/1813
C.TCP/1812
D.TCP/1813