2016年7月25日以降に400-101試験を改訂予定です。
400-101試験の改訂には、最新テクノロジードメインの追加、および 筆記試験とラボ試験のドメインをモジュールにまとめ一本化することが含まれます。
CCIE Routing and Switching 筆記試験 v5.0（400-101）は試験数:90 - 110 問)、試験時間: 120、試験言語:英語の対応のCisco CCIE Routing and Switching認定の試験です。
400-101認定試験の受験者は筆記試験に合格した後、対応するハンズオンラボ試験に合格する必要があります。
400-101試験を受けるにあたり、。Passexamを勉強することを推奨します。
PassexamのCisco CCIE Routing and Switching認定400-101問題集を使用すると、IT業界でより良い発展を持つことになります。
弊社の400-101勉強対策を使用すると、試験に合格するのに役立ちます。
Cisco CCIE Routing and Switching認定400-101試験のブループリントに掲載されているトピックについて深い理解を有していることが望ましく、3〜5年の実務経験を経てから受験することを強く推奨します。
PassexamはCisco CCIE Routing and Switching認定400-101試験の候補者のための訓練の20時間で最新の短期有効な問題集を開発しました。
Passexamの400-101受験対策は唯一の合理的な価格を持って、受験者のために多くの時間を節約します。
Cisco CCIE Routing and Switching認定
400-101試験の出題範囲には、以下のトピックが含まれます
1.0 ネットワークの原則
2.0 レイヤ 2 テクノロジー
3.0 レイヤ 3 テクノロジー
4.0 VPN テクノロジー
5.0 インフラストラクチャのセキュリティ
6.0 インフラストラクチャ サービス
400-101試験材料は最も包括的な認証規格の産業訓練方法を提供するようPassexamが認識されています。
弊社のCisco CCIE Routing and Switching認定400-101問題集の品質は非常に良好であり、非常に高速な更新レートを持っています。
真実の400-101試験問題を全部にカバー、400-101問題集の費用すぐに全額で返金いたします。
真剣にCisco CCIE Routing and Switching認定400-101参考書を勉強する限り、受験したい400-101試験に楽に合格することができるということです。
1.A TCP/IP host is able to transmit small amounts of data (typically less than 1500 bytes), but attempts to
transmit larger amounts of data hang and then time out.What is the cause of this problem?
A.A link is flapping between two intermediate devices.
B.The processor of an intermediate router is averaging 90 percent utilization.
C.A port on the switch that is connected to the TCP/IP host is duplicating traffic and sending it to a port
that has a sniffer attached.
D.There is a PMTUD failure in the network path.
Answer:D
Explanation:
Sometimes, over some IP paths, a TCP/IP node can send small amounts of data (typically less than 1500
bytes) with no difficulty, but transmission attempts with larger amounts of data hang, then time out.Often
this is observed as a unidirectional problem in that large data transfers succeed in one direction but fail in
the other direction.This problem is likely caused by the TCP MSS value, PMTUD failure, different LAN
media types, or defective links.
Reference:
http://www.cisco.com/c/en/us/support/docs/additional-legacy-protocols/ms-windows-networking/13709-3
8.html
2.Which three conditions can cause excessive unicast flooding? (Choose three.)
A.Asymmetric routing
B.Repeated TCNs
C.The use of HSRP
D.Frames sent to FFFF.FFFF.FFFF
E.MAC forwarding table overflow
F.The use of Unicast Reverse Path Forwarding
Answer:A, B, E
Explanation:
Causes of Flooding
The very cause of flooding is that destination MAC address of the packet is not in the L2 forwarding table
of the switch.In this case the packet will be flooded out of all forwarding ports in its VLAN (except the port
it was received on).Below case studies display most common reasons for destination MAC address not
being known to the switch.
Cause 1: Asymmetric Routing
Large amounts of flooded traffic might saturate low-bandwidth links causing network performance issues
or complete connectivity outage to devices connected across such low-bandwidth links.
Cause 2: Spanning-Tree Protocol Topology Changes
Another common issue caused by flooding is Spanning-Tree Protocol (STP) Topology Change
Notification (TCN).TCN is designed to correct forwarding tables after the forwarding topology has
changed.This is necessary to avoid a connectivity outage, as after a topology change some destinations
previously accessible via particular ports might become accessible via different ports.TCN operates by
shortening the forwarding table aging time, such that if the address is not relearned, it will age out and
flooding will occur.
TCNs are triggered by a port that is transitioning to or from the forwarding state.After the TCN, even if the
particular destination MAC address has aged out, flooding should not happen for long in most cases since
the address will be relearned.The issue might arise when TCNs are occurring repeatedly with short
intervals.The switches will constantly be fast-aging their forwarding tables so flooding will be nearly
constant.
Normally, a TCN is rare in a well-configured network.When the port on a switch goes up or down, there is
eventually a TCN once the STP state of the port is changing to or from forwarding.When the port is
flapping, repetitive TCNs and flooding occurs.
Cause 3: Forwarding Table Overflow
Another possible cause of flooding can be overflow of the switch forwarding table.In this case, new
addresses cannot be learned and packets destined to such addresses are flooded until some space
becomes available in the forwarding table.New addresses will then be learned.This is possible but rare,
since most modern switches have large enough forwarding tables to accommodate MAC addresses for
most designs.
Forwarding table exhaustion can also be caused by an attack on the network where one host starts
generating frames each sourced with different MAC address.This will tie up all the forwarding table
resources.Once the forwarding tables become saturated, other traffic will be flooded because new
learning cannot occur.This kind of attack can be detected by examining the switch forwarding table.Most
of the MAC addresses will point to the same port or group of ports.Such attacks can be prevented by
limiting the number of MAC addresses learned on untrusted ports by using the port security feature.
Reference:
http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6000-series-switches/23563-143.html#caus
es
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