OMC911370 GSM IPRAN Maintenance and Test Tools ISSUE1.00

GSM IPRAN Maintenance and Test Tools

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RAN is short for radio access network.

The end-to-end (E2E) maintenance mode is used in the synchronous digital hierarchy

(SDH). However, the maintenance for mobile IP bearer networks is invisible

The route, E2E tunnels, and bearer service quality are invisible.

During the O&M, active monitoring and passive maintenance and test are combined.



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Background

Internet Control Message Protocol (ICMP) is a subprotocol of the TCP/IP suite. It

is used to transmit control messages between IP hosts and routers.

Internet Group Management Protocol (IGMP) is a multicast protocol of the IP

suite. It is used by an IP host to report to any directly-connected router member

information of the protocol.

Reverse Address Resolution Protocol (RARP) allows physical device in the local

area network (LAN) to request an IP address from the ARP list or cache on the

gateway server.

The fiber distributed data interface (FDDI) technology provides the highest

transmission rate among all mature LAN technologies. It relies on ANSIX3T9.5 to

achieve a maximum rate of 100 Mbit/s.

X.25 is the first connection-oriented network and the first public data network. It

was developed before the open systems interconnection (OSI) model.



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ICMP is regarded as part of the network layer. ICMP packets transmit error, control

packets, and query results. They are used by protocols at network layer or higher layers,

such as TCP or UDP.

Ping operates by sending ICMP echo request packets to the target host and waiting for an

ICMP reply packet. If an echo reply packet is sent back to the source host within the

specified time period after the echo request packets reach the target host, the target host

is reachable. If the source host fails to receive an echo reply packet within the specified

time period, a timeout is displayed at the transmit end.

Ping sets the identifier in an ICMP packet to the procedures that sends the ICMP packet.

This helps to identify at the peer end different ping cases that run at the local end.

Sequence Number is incremented by 1 when Ping sends an ICMP echo request packet. The

number of echo request packets sent varies with different types of device.



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At present, IP RAN devices only support IPv4 tests.

Identify faults in network quality: For example, packet losses, transmission delay, and delay

variation.



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TTL is short for time to live. The TTL field in an IP header specifies the time period when

the data packets live and the maximum number of routers to traverse. TTL is configured

on the source device that sends data packets. Its value decreases by 1 when the data

packets traverse a router. When the TTL value decreases to 0, the data packets are

discarded, and an ICMP timeout packet is sent to the source device as a notification.

Under normal circumstances, the TTL value is set to the number of routers to traverse.

You can stop the Ping IP test by pressing CTRL+Q.



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As part of the network layer, ICMP packets transmit error, control packets, and query

results. They are used by protocols at network layer or higher layers, such as TCP and UDP.

The TTL field in an IP header specifies the time period when the data packets live and the

maximum number of routers to traverse. TTL is configured on the source device that sends

data packets. Its value decreases by 1 when the data packets traverse a router. When the

value decreases to 0, the data packets are discarded, and an ICMP timeout packet is sent

to the source device as a notification. Under normal circumstances, the TTL value is set to

the number of routers to traverse.

First, the source host sends to the target host three UDP data packets whose TTL value is 1,

a port whose ID is greater than 32768 is randomly used as the port for receiving the data

packets at the receive end. When the data packets reach a router, a timeout occurs, and

the source host receives an ICMP timeout packet from the router. Then, the source host

sends again three UDP data packets whose TTL value is 2, and receives an ICMP timeout

packet from the second router that the data packets traverse. This continues until the

target host receives the packets.

The packets that the source device sends contain the destination port ID. If the port is not

used on the target device when the ICMP packets are received, the target device sends

ICMP port unreachable information back to the source device, indicating that the target

device is unreachable and the Tracert operations are performed. The route is also shown in

the results displayed on the source device.

The maximum value of TTL in a data packet is 30. If no response packet is received by the

source host within the time specified, timeout information is displayed on the source

device. If timeout information is still displayed when the TTL value is 30, the packets

cannot reach the target host, and the test fails.



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If the IP address at the local end of an IP route equals the source IP address of Trace Route,

the IP address at the peer end of the IP route equals the destination IP address of Trace

Route, and ping detection is enabled, the Trace Route results are inaccurate. This situation

is normal.

If the source IP address is not specified, the system selects the most appropriate interface

IP address based on PHB and uses the IP address as the source IP address. Ensure that

routes to the source IP address are configured for intermediary and destination devices.



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Conclusion:The Tracert packets fail to reach the target host after going through two routers. Therefore, the route after the second router is faulty.



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The Outer Intercept Length or Inner Intercept Length parameter specifies the length

of each Ethernet frame (especially the long packet) to be captured. Only the packet of the

length specified by the parameter is intercepted and the part exceeding the specified

length is not reported. If the actually captured packet is shorter than the specified length,

the length of the actual packet is used.

Packet capturing is used to obtain and analyze external packets.

External parameters:



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When the packets are captured, the tracing files are saved in the OMU. You can obtain the

files from the /bam/common/fam/trace/ directory using FTP.



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Ethereal is a commonly used IP network packet capturing and analysis tool, you can

download it from the Internet.



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Documents

OMC911370 GSM IPRAN Maintenance and Test Tools ISSUE1.00