Flashcards #3
What does the vSmart controller do?
manages the control plane of SD-WAN overlay network architecture. It is the brain an enforces the policies.
What is 802.11i?
It is a standard the defines the encryption method off AES 128-bit, 192-bit, and 256-bit
What is the MTU?
It is the largest fram that a device can transmit.
The default for an Ethernet frame is 1500 bytes. Because an IP packet has a 20 byte header, the largest IP payload that can be carried in an Ethernet frame is 1480 bytes.
What happens if a frame exceeds the MTU?
the frame will be fragmented if possible or discarded if the do-not-fragment bit is set
OSPFv3 LSA’s list
Type 3 - Inter Area prefix LSAs Type 4 - Inter Area router LSAs Type 5 - Autonomous System (AS) external LSAs Type 8 - Link LSAs Type 9- Intra-area prefix LSAs
OSPFv3 Type 3 LSA?
Inter Area prefix LSAs for area border routers (ABRs).
Type 3 LSAs are used to advertise internal networks to other ares
OSPFv3 Type 4 LSA?
Inter Area router LSAs for autonomous system boundary routers (ASBRs)
Type 4 LSAs are used to advertise the location of an autonomous system boundary routers (ASBR) so that routers can determine the best next-hop path
OSPFv3 Type 5 LSA?
Autonomous System (AS) external LSAs
Type 5 LSAs are used to advertise routes that are redistributed into OSPF
OSPFv3 Type 8 LSA?
Are used to to advertise the routers link local IPv6 address, prefix, and option information.
These LSAs are never flooded outside the local link
OSPFv3 Type 9 LSA?
Intra-area prefix LSAs
Type 9 LSAs carry IPv6 prefix information, much like OSPFv2 Type 1 and Type 2 LSAs carry IP version 4 prefix information
How can you tell if a VLAN is prned from the outut of show interfaces trunk?
If the VLANs are listed under:
** “VLANS ALLOWED AND ACTIVE IN MANAGEMENT DOMAIN”
but are not listed under:
** “VLANS IN SPANNING TREE FORWARDING STATE AND NOT PRUNED”
are either pruned or are blocked by STP
Where is traffic shaping applied? Traffic thats inbound, outbound, or both?
It is applied to only Outbound traffic
Where is traffic policing applied? Traffic thats inbound, outbound, or both?
Traffic policing is applied to both inbound and outbound traffic
What two actions would cause all the wireless clients on the network to lose connectivity
- Changing the SSID on the AP
* Changing the encryption key on the AP
What is the TCP MSS setting for a Cisco Router that is originating data destined for a remote IP network?
536 bytes
MSS = Maximum segment size. Can be used to restrict outgoing TCP segments to a segment size that is small enough to avoid fragmenting the IP datagram, thereby avoiding the performance problems that can occur as a result of IP fragmentation.
The smallest MTU that can be used on IPv4 network is 576 bytes. The 546 byte default MSS value is derived by subtracting the 20 byte TCP header and the 20 byte IP header
What is the TCP MSS setting for a Cisco router that is sending data destined for a local LAN?
1460 bytes.
What is MACSec?
802.1AE
Once a host is authenticated with 801.1x, the frames that travel between the host and the access switch are encrypted. Therefore, MACsec secures communications for traffic at Layer 2 of the OSI networking model. The frames are only encrypted when they are on the wire between the host and the switch.
The frames are decrypted by the switch and then forwarded accordingly. If the frames are intended for another MACsec host on the same switch, the switch will encrypt the frames before it forwards them to the host; by contrast, if the the frames are intended for a destination on another switch, they will be forwarded without encryption.
Which VTP Modes allow the creation, modification, and deletion of VLANs on a switch
Only Server and Transparent Mode.
Switches in VTP transparent mode do not participate in VTP synchronization. However, if transparent mode swithces that are running VTP v2 or higher will forward VTP advertisements out all of their trunk ports. VLANs that are created , modified, or deleted on a transparent mode switch will affect only that transparent mode swithc.
What is LAG?
Link Aggregation. LAG enables multiple physical ports on a wireless LAN controller (WLC) to operate as one logical group. Thus LAG enables Load Balancing across links between devices, and Load Balancing.
If the connected switch is configured for LACP or PAgP, the LAG will not form.
How many bytes does the GRE tunel key add to the header of encapsulated packets?
4 bytes.
GRE is a Cisco-propriety protocol that can tunnel traffics from one network to another without requiring that the transport network support the network protocols in use at the tunnel source or tunnel destination.
Because GRE main focus is to transport many different protocols, it has limited security features. So it needs to be combined with IPsec whcih can be configured ti encrypt both the header and payload of tunneled traffic.
What wireless network is most vulnerable to interference from a microwave over?
802.11b
Supports the lowest of all the 802.11 standards in terms of maximum data throughput (11Mbs)
Operates in the 2.3GHz range with max distance of 300 feet.
Many household devices also use the 2.4 GHz range (microwave ovens, cordless phones) So these devices are more likely to encounter interference than devices that use the 5.0 GHz
What HTTP status code indicates that the requested resource could not be found on the server?
404
What is the LAP discovery process steps?
- LAP first obtains an address from a DHCP server
- After received address, LAP scans DHCP server response for a option 43, whcih identifies the address of a WLC
2a. If Option 43 not present, will use the DNS server (Address obtained via the DHCP in first step) to attempt to resolve the host name CISCO-CAPWAP-CONTROLLER.
2c. If DNS is not configured, LAP will send out a L3 broadcast on the segment,
What is the Cisco Propriety channel-group method?
PAgP
Auto and Desirable
What is a Non Cisco-Propriety channle-group method?
LACP
Active and Passive
What is Cisco Mobility Express?
Provides the convenience of having a wireless LAN controller (WLC) at branch locations without investing in a dedicated WLC for each branch. Any Cisco 802.11ac access point (AP) that supports CAPWAP can be converted to a WLC by installing the Cisco Mobility Express image for that AP.
